One of the great cybersecurity challenges organizations currently face, especially smaller ones, is that they don’t know what they don’t know. 

It’s tough to have your eyes on everything all the time, especially with so many pieces of software running and IoT devices extending the reach of networks broader than ever.  

One potential (and free!) solution seems to be a new program from the U.S. Cybersecurity and Infrastructure Security Agency (CISA) that alerts companies and organizations of unpatched vulnerabilities that attackers could exploit.  

Under a pilot program that’s been running since January 2023, CISA has sent out more than 2,000 alerts to registered organizations regarding the existence of any unpatched vulnerabilities in CISA’s Known Exploited Vulnerabilities (KEV) catalog. For those that don’t know, the KEV catalog consists of any security issues that threat actors are known to actively exploit in the wild, and often include some of the most serious vulnerabilities disclosed on a regular basis, some of which have been around for years. 

Jen Easterly, CISA’s director, said last month that 49 percent of those vulnerabilities that CISA sent alerts about were mitigated — either through patching or other means. The program will launch in earnest later this year, but more than 7,000 organizations have already registered for the pilot program. 

Everything about this makes sense to me — it comes at no cost to the consumer or business, it allows the government to inform organizations of something they very likely aren’t aware of, and these issues are easy enough to fix with software or hardware patches.  

I’m mainly wondering how we’ll get more potential targets to sign up for this program and receive these alerts. 

According to CISA’s web page on the program, the alerts are only currently available to “Federal, state, local, tribal and territorial governments, as well as public and private sector critical infrastructure organizations.” 

I would imagine that, at some point, the scope of this will be expanded if it continues to be successful, and there are no clear guidelines for what “critical infrastructure” means in this context, exactly. (For example, would something like a regional ISP would be eligible for this program? I’d consider this CI, but I’m not sure the federal government would.) 

Currently, signing up for the alerts seems to be as simple as sending an email. CISA’s also been sending alerts to any vulnerable systems that appear on Shodan scans. I don’t think there’s a way to make something like this compulsory unless it’s codified into law somewhere, but it almost seems like it should be. 

Who wouldn’t want to just get free alerts from the federal government telling you when your network has a vulnerability that’s being exploited in the wild? For many of the local and state government teams, the pilot program targets are understaffed and underfunded, and sometimes the act of patching can get so overwhelming that it can take months to keep current. But this type of organization may also be stretched thin to the point they haven’t even heard of this program from CISA. So if the most I can do is shout out this government program in this newsletter and one extra company signs up, I’ll feel good about that.  

The one big thing 

Cisco Talos’ Vulnerability Research team recently disclosed three zero-day vulnerabilities two of which are still unpatched as of Wednesday, May 8. Two vulnerabilities in this group — one in the Tinyroxy HTTP proxy daemon and another in the stb_vorbis.c file library — could lead to arbitrary code execution, earning both issues a CVSS score of 9.8 out of 10. While we were unable to reach the maintainers, the Tinyproxy maintainers have since patched the issue. Another zero-day exists in the Milesight UR32L wireless router. These vulnerabilities have all been disclosed in adherence to Cisco’s third-party vulnerability disclosure timeline after the associated vendors did not meet the 90-day deadline for a patch or communication.   

Why do I care? 

Tinyproxy is meant to be used in smaller networking environments. It was originally released more than a dozen years ago. A use-after-free vulnerability, TALOS-2023-1889 (CVE-2023-49606), exists in the `Connection` header provided by the client. An adversary could make an unauthenticated HTTP request to trigger this vulnerability, setting off the reuse of previously freed memory, which leads to memory corruption and could lead to remote code execution. Four of these issues that Talos disclosed this week still do not have patches available, so anyone using affected software should find other potential mitigations. 

So now what? 

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

Top security headlines of the week 

Several international law enforcement agencies have identified, sanctioned and indicted the alleged leader of the LockBit ransomware group. Russian national Dmitry Yuryevich Khoroshev has been unmasked as the person behind the operator of the username “LockBitSupp,” LockBit’s creator and mastermind. The ransomware group has extorted an estimated $500 million from its victims over its several years of activity. Khoroshev allegedly took 20 percent of each ransom payment and operated the group’s data leak site. The U.S. federal government is offering up to a $10 million reward for anyone who can provide information leading to Khoroshev’s arrest. In all, he is charged with 26 crimes in the U.S. that carry a maximum punishment of 185 years in prison. LockBit, founded around 2018, operates under the ransomware-as-service model in which other actors can pay to access LockBit’s malware and infection tools. The group has been linked to several major ransomware attacks over the years, including against the U.K.’s Royal Mail service, a small Canadian town in Ontario and a children’s hospital in Chicago. (Wired, The Verge) 

The U.K. blamed Chinese state-sponsored actors for a recent data breach at a military contractor that led to the theft of personal information belonging to around 270,000 members of the British armed forces. Potentially affected information includes names and banking information for full-time military personnel and part-time reservists, as well as veterans who left the military after January 2018. Some of those affected are also current members of parliament. A top official at the U.K.’s Ministry of Defense called the breach a “very significant matter” and that the contractor immediately took the affected systems offline. While the British government has yet to formally attribute the attack to a specific threat actor, several reports indicate they believe an actor emanating from China was responsible. While the actors may have been present on the network for up to weeks, there is currently no evidence that the information was copied or removed. (The Guardian, Financial Times) 

Security researchers found a new attack vector that could allow bad actors to completely negate the effect of VPNs. The method, called “TunnelVision,” can force VPN services to send or receive some or all traffic outside of the encrypted tunnel they create. Traditionally users will rely on VPNs to protect their traffic from snooping or tampering, or to hide their physical locations. The researchers believe TunnelVision affects every VPN application available if it connects to an attacker-controlled network. There is currently no way to avoid or bypass these attacks unless the VPN runs on Linux or Android. TunnelVision has been possible since at least 2002, though it's unclear how often it's been used in the wild. VPN users who are concerned about this attack can run their VPN inside a virtual machine whose network adapter isn’t in bridged mode or connect via the Wi-Fi network of a cellular device. However, for the attack to be effective, the attacker would need complete control over a network. If a connection is affected, though, the user would be completely unaware, and the VPN would not alert them to a change. (Ars Technica, ZDNet) 

Can’t get enough Talos? 

• Talos Takes Ep. #182: 4 takeaways from what Talos IR is seeing in the field 
• ClamAV 1.4.0 release candidate now available! 
• Critical Tinyproxy Flaw Opens Over 50,000 Hosts to Remote Code Execution 
• Vulnerabilities in employee management system could lead to remote code execution, login credential theft 

Upcoming events where you can find Talos 

ISC2 SECURE Europe (May 29) 

Amsterdam, Netherlands 

Gergana Karadzhova-Dangela from Cisco Talos Incident Response will participate in a panel on “Using ECSF to Reduce the Cybersecurity Workforce and Skills Gap in the EU.” Karadzhova-Dangela participated in the creation of the EU cybersecurity framework, and will discuss how Cisco has used it for several of its internal initiatives as a way to recruit and hire new talent.  

Cisco Live (June 2 - 6) 

Las Vegas, Nevada  

Most prevalent malware files from Talos telemetry over the past week  

SHA 256: c67b03c0a91eaefffd2f2c79b5c26a2648b8d3c19a22cadf35453455ff08ead0  
MD5: 8c69830a50fb85d8a794fa46643493b2  
Typical Filename: AAct.exe  
Claimed Product: N/A   
Detection Name: W32.File.MalParent 

SHA 256: d529b406724e4db3defbaf15fcd216e66b9c999831e0b1f0c82899f7f8ef6ee1 
MD5: fb9e0617489f517dc47452e204572b4e 
Typical Filename: KMSAuto++.exe 
Claimed Product: KMSAuto++ 
Detection Name: W32.File.MalParent 

SHA 256: abaa1b89dca9655410f61d64de25990972db95d28738fc93bb7a8a69b347a6a6 
MD5: 22ae85259273bc4ea419584293eda886 
Typical Filename: KMSAuto++ x64.exe 
Claimed Product: KMSAuto++ 
Detection Name: W32.File.MalParent 

SHA 256: 8664e2f59077c58ac12e747da09d2810fd5ca611f56c0c900578bf750cab56b7  
MD5: 0e4c49327e3be816022a233f844a5731  
Typical Filename: aact.exe  
Claimed Product: AAct x86  
Detection Name: PUA.Win.Tool.Kmsauto::in03.talos 

SHA 256: 59f1e69b68de4839c65b6e6d39ac7a272e2611ec1ed1bf73a4f455e2ca20eeaa   
MD5: df11b3105df8d7c70e7b501e210e3cc3   
Typical Filename: DOC001.exe   
Claimed Product: N/A   
Detection Name: Win.Worm.Coinminer::1201 

Cisco Talos’ Vulnerability Research team recently disclosed three zero-day vulnerabilities that are still unpatched as of Wednesday, May 8. 

Two vulnerabilities in this group — one in the Tinyroxy HTTP proxy daemon and another in the stb_vorbis.c file library — could lead to arbitrary code execution, earning both issues a CVSS score of 9.8 out of 10. While we were unable to reach the maintainers, the Tinyroxy maintainers have since patched the issue.  

Another zero-day exists in the Milesight UR32L wireless router. 

These vulnerabilities have all been disclosed in adherence to Cisco’s third-party vulnerability disclosure timeline after the associated vendors did not meet the 90-day deadline for a patch or communication.  

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

Use-after-free vulnerability in Tinyproxy daemon 

Discovered by Dimitrios Tatsis. 

The Tinyproxy HTTP proxy daemon contains a vulnerability that could lead to arbitrary code execution. 

Tinyproxy is meant to be used in smaller networking environments. It was originally released more than a dozen years ago.  

A use-after-free vulnerability, TALOS-2023-1889 (CVE-2023-49606), exists in the `Connection` header provided by the client. An adversary could make an unauthenticated HTTP request to trigger this vulnerability, setting off the reuse of previously freed memory, which leads to memory corruption and could lead to remote code execution. This issue has been patched, though Talos initially released it as a zero-day when no patch was available.

Milesight UR32L firmware update vulnerability 

Discovered by Francesco Benvenuto. 

The Milesight UR32L wireless router contains a vulnerability that could force the device to implement any firmware update, regardless of its legitimacy.  

TALOS-2023-1852 (CVE-2023-47166) exists because the UR32L, an industrial cellular router, never checks the validity of the uploaded firmware. This could allow an adversary to upgrade the router with arbitrary firmware they created. 

Talos has previously covered how an adversary could chain together several other vulnerabilities in the UR32L to completely take over the device. Talos released 22 security advisories in July 2023, nine of which have a CVSS score greater than 8. 

Buffer overflow vulnerability in open-source single-header file library could lead to arbitrary code execution 

Discovered by Emmanuel Tacheau. 

A heap-based buffer overflow vulnerability exists in the comment functionality of stb _vorbis.c, an open-source, single-header file library used to decode Ogg Vorbis non-proprietary audio files. Ogg Vorbis is an open-source, patent- and royalty-free, general-purpose compressed audio format. 

TALOS-2023-1846 (CVE-2023-47212) is triggered if an adversary sends the target a specially crafted .ogg file, which can lead to an out-of-bounds write. With enough heap grooming, an adversary could use this vulnerability to achieve arbitrary code execution. 

Brute force attacks are one of the most elementary cyber threats out there. Technically, anyone with a keyboard and some free time could launch one of them — just try a bunch of different username and password combinations on the website of your choice until you get blocked.  

Nick Biasini and I discussed some of the ways that organizations can defend against brute force attacks since detection usually doesn’t fall into the usual bucket (ex., there’s nothing an anti-virus program could detect running). But a good place to start just seems to be implementing strong password rules, because people, unsurprisingly, are still using some of the most obvious passwords that anyone, attacker or not, would guess. 

Along with our advisory on a recent increase in brute force attacks targeting SSH and VPN services Cisco Talos published a list of IP addresses associated with this activity, along with a list of usernames and passwords adversaries typically try to use to gain access to a network or service. 

There are some classics on this list — the ever-present “Password” password, Passw0rd (with a zero, not an “O”) and “123456.” This tells me that users still haven’t learned their lesson. It’s somewhat funny to think about some well-funded actor just being like, “Well, let me try to ‘hack’ into this machine by using ‘123456’” as if they’re in a parody movie, but if they already can guess a username based off someone’s real name, it’s not that unlikely that password is being used somewhere. 

A few other example passwords stood out to me: “Mart1x21,” because I can’t tell if this is just someone named “Martin” or a play on the month of March, and things like “Spring2024x21” and “April2024x21” because I appreciate the idea that someone using that weak of a password thinks that adding the extra three characters onto “April2024” is really going to throw an attacker off. 

Looking at this list got me thinking about what some potential solutions are to the internet’s password problem, and our ever-present battle to educate users and warn them about the dangers of using weak or default passwords. 

Going passwordless is certainly one option because if there just are no passwords to log in, there’s nothing text-based an attacker could just start guessing. 

The best solution I’ve seen recently is that the U.K. literally made a law requiring hardware and software manufacturers to implement stronger security standards. The Product Security and Telecommunications Infrastructure (PSTI) that went into effect last month contains a range of security protections companies must follow, but they now include mandatory password rules that will force users to change default passwords when registering for new accounts and stop them from using easy-to-guess passwords like “Admin” and “12345.”  

It would be great if users would just stop using these credentials on their own, but if attackers are still thinking that someone out there is using “Password” as their password, they probably are.  

The one big thing 

For the first time in several quarters, business email compromise (BEC) was the most common threat in Cisco Talos Incident Response (Talos IR) engagements during the first quarter of 2024. BEC made up 46 percent of all engagements in Q1, a significant spike from Q4 2023, according to the latest Talos IR Quarterly Trends Report. Ransomware, which was the top-observed threat in the last quarter of 2023, decreased by 11 percent. Talos IR also observed a variety of threats in engagements, including data theft extortion, brute-force activity targeting VPNs, and the previously seen commodity loader Gootloader. 

Why do I care? 

BEC is a tactic adversaries use to disguise themselves as legitimate members of a business and send phishing emails to other employees or third parties, often pointing to a malicious payload or engineering a scheme to steal money. The use of email-hiding inbox rules was the top-observed defense evasion technique, accounting for 21 percent of engagements this quarter, which was likely due to an increase in BEC and phishing within engagements. These are all valuable insights from the field provided in Talos IR’s full report. 

So now what? 

There are some known indicators of compromise that customers can look for if they suspect The lack of MFA remains one of the biggest impediments for enterprise security. All organizations should implement some form of MFA, such as Cisco Duo. The implementation of MFA and a single sign-on system can ensure only trusted parties are accessing corporate email accounts, to prevent the spread of BEC. If you’d like to read about other lessons from recent Talos IR engagements, read the one-pager here or the blog post here. 

Top security headlines of the week 

The chief executive of UnitedHealth Group testified to U.S. Congress on Wednesday regarding the recent cyber attack against Change Healthcare. Change’s operations went nearly completely dark for weeks earlier this year after a data breach, which likely resulted in millions of patients’ records and personal information being accessed. Lawmakers questioned whether UnitedHealth was too involved in the nation’s medical systems, as Change manages a third of all American patient records and processes more than 15 billion transactions a year at doctor’s offices, hospitals and other medical providers. As a result of the outage, some healthcare practitioners went more than a month without being paid, and many had to tap into their personal funds to keep offices open. UnitedHealth’s CEO told Congress the company was still working to figure out the full extent of the campaign and was talking to U.S. agencies about how to best notify individuals who were affected. The hearing has also generated a conversation around consolidation in the American healthcare industry and whether some groups are controlling too much of the patient base. (The New York Times, CNBC) 

Vulnerabilities in a popular phone tracking app could allow anyone to view all users’ locations. A security researcher recently found that iSharing, which allows users to see the exact location of a device, contains a vulnerability that prevented the app's servers from conducting proper checks of user data access. iSharing is advertised as an app for users who want to track friends' and family members’ locations or as an extra layer of security if their device were to be lost or stolen. The flaws also exposed users’ names, profile pictures, email addresses and phone numbers. The researcher who discovered the vulnerability was able to show a proof-of-concept exploitation almost immediately after creating a brand new account on the app. Representatives from the developers of iSharing told TechCrunch that the company’s logs did not show any signs of the vulnerability being exploited prior to the researcher’s disclosure. These types of apps can also be used as “stalkerware,” in which someone who knows a targeted user quietly downloads the app on a target’s phone, and then uses it to remotely track their location. (TechCrunch) 

Adversaries are hiding malware in GitHub comments, disguising malicious code as URLs associated with Microsoft repositories, and making the files appear trustworthy. Although some security researchers view this as a vulnerability, Microsoft maintains that it is merely a feature of using GitHub. While adversaries have so far mainly abused this feature to mirror Microsoft URLs, it could theoretically be used to create convincing lures on any GitHub repository. When a user leaves a comment in GitHub, they can attach a file, which is then uploaded to GitHub’s CDN and associated with the related project using a unique URL. GitHub automatically generates the link to download that attachment after adding the file to an unsaved comment, allowing threat actors to attach malware to any repository without the administrators knowing. This method has already been abused to distribute the Readline information-stealing trojan by attaching comments to Microsoft’s GitHub-hosted repositories for “vcpkg” and “STL.” The malicious URL will even still work if the poster deletes the comment, allowing them to reuse the GitHub-generated URL. (Bleeping Computer, Dark Reading) 

Can’t get enough Talos? 

• Cisco Talos at RSAC 2024 
• Cisco Zero-Days Anchor 'ArcaneDoor' Cyber-Espionage Campaign 
• Governments issue alerts after 'sophisticated' state-backed actor found exploiting flaws in Cisco security boxes 
• Vulnerabilities in employee management system could lead to remote code execution, login credential theft 
• Researcher Spotlight: James Nutland studies what makes threat actors tick, growing our understanding of the current APT landscape 

Upcoming events where you can find Talos

RSA (May 6 - 9) 

San Francisco, California    

ISC2 SECURE Europe (May 29) 

Amsterdam, Netherlands 

Gergana Karadzhova-Dangela from Cisco Talos Incident Response will participate in a panel on “Using ECSF to Reduce the Cybersecurity Workforce and Skills Gap in the EU.” Karadzhova-Dangela participated in the creation of the EU cybersecurity framework, and will discuss how Cisco has used it for several of its internal initiatives as a way to recruit and hire new talent.  

Cisco Live (June 2 - 6) 

Las Vegas, Nevada  

Most prevalent malware files from Talos telemetry over the past week 

This section will be on a brief hiatus while we work through some technical difficulties. 

Cisco Talos’ Vulnerability Research team has disclosed more than a dozen vulnerabilities over the past three weeks, five in a device that allows employees to check in and out of their shifts, and another that exists in an open-source library used in medical device imaging files. 

The Peplink Smart Reader contains several vulnerabilities, including one issue that could allow an adversary to obtain the administrator’s login credentials and the MD5-hashed version of their password. 

Talos also recently helped to responsibly disclose and patch other vulnerabilities in the Foxit PDF Reader and two open-source libraries that support the processing and handling of DICOM files. 

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

Code execution, information disclosure vulnerabilities in Peplink Smart Reader 

Discovered by Matt Wiseman. 

The Peplink Smart Reader is an internet-connected device associated with the PepXIM Time-Logging and Security System. Companies’ employees use this device to check in and out of their shifts, allowing administrators to keep track of time cards and pay. It also can control access to certain buildings, and even public transportation. 

There are two information disclosure vulnerabilities, TALOS-2023-1863 (CVE-2023-43491) and TALOS-2023-1865 (CVE-2023-45209), that are triggered if an adversary sends a specially crafted HTTP message to the targeted device.  

If successful, the attacker could eventually view the active administrator’s username and MD5-hased password. And in the case of TALOS-2023-1865, it goes a step further, potentially allowing the adversary to view wireless network credentials, network configuration details and SNMP configuration details. 

With those credentials (or admin credentials obtained by other means), an adversary could exploit TALOS-2023-1868 (CVE-2023-40146), a privilege escalation vulnerability in the Smart Reader. An adversary could execute a specially crafted command line argument to cause a limited-shell escape and execute unblocked, default busybox functionality to eventually gain access to an uninhibited root shell. 

TALOS-2023-1866 (CVE-2023-45744) is also triggered by a specially crafted HTTP request, but in this case, could allow an adversary to manipulate certain configuration settings on the device. 

The most serious of the issues Talos discovered in the Smart Reader is TALOS-2023-1867 (CVE-2023-39367), a command injection vulnerability that could allow an attacker to execute arbitrary commands. This vulnerability has a 9.1 CVSS score out of 10. An authenticated attacker can leverage this vulnerability to execute arbitrary commands on the device with root privileges and elevate their access to the vulnerable system. 

Silicon Labs Gecko Platform invalid pointer dereference vulnerability 

Discovered by Kelly Patterson. 

An invalid pointer dereference vulnerability exists in the HTTP server header parsing functionality of the Silicon Labs Gecko Platform.  

The Gecko Platform SDK is the collection of Silicon Labs’ wireless software development kits and Gecko Platform into an integrated package. It allows users to develop applications inside Silicon Labs’ internet-of-things software ecosystem. 

TALOS-2024-1945 (CVE-2023-51391) is triggered if an adversary sends the target a specially crafted network packet, which could lead to a denial-of-service condition. 

Incorrect type conversion vulnerability in open-source library for DICOM files 

Discovered by Emmanuel Tacheau. 

There is an incorrect type conversion vulnerability in OFFIS DCMTK, an open-source library often used to manage, store and convert DICOM files. DICOM is the commonly used file type to transfer, send and store medical imaging files, such as X-rays and ultrasounds.  

Hospitals and companies use DCMTK for various purposes, ranging from product testing to being a building block for research projects, prototypes and commercial products. 

TALOS-2024-1957 (CVE-2024-28130) could allow an adversary to execute arbitrary code on the targeted machine if they trick the user into opening a specially crafted file.  

Out-of-bounds write vulnerabilities in Grassroots DICOM library 

Discovered by Emmanuel Tacheau. 

Another open-source library for handling DICOM files, Grassroots DiCoM, contains three out-of-bounds writer vulnerabilities.  

TALOS-2024-1944 (CVE-2024-25569) and TALOS-2024-1935 (CVE-2024-22373) can be triggered if an adversary tricks the target into opening a specially crafted, malicious DICOM file, eventually allowing them to read out-of-bounds memory. 

TALOS-2024-1924 (CVE-2024-22391) works in the same way, but in this case, causes a heap-based buffer overflow, leading to memory corruption.  

Three vulnerabilities in Foxit PDF Reader could lead to arbitrary code execution 

Discovered by KPC. 

Three vulnerabilities exist in Foxit PDF Reader that could allow an adversary to execute arbitrary code on the targeted machine. 

Foxit PDF Reader is one of the most popular pieces of PDF-reading software currently available and aims to have feature parity with Adobe Acrobat Reader. It also includes a browser plugin to allow users to open files in their web browsers.  

TALOS-2024-1959 (CVE-2024-25648) and TALOS-2024-1958 (CVE-2024-25938) are use-after-free vulnerabilities that can be triggered if an attacker tricks a user into opening a malicious, specially crafted PDF. This could also work if the user has the browser plugin enabled and the adversary tricks them into opening an attacker-controlled webpage. These vulnerabilities could lead to a use-after-free issue, potentially leading to memory corruption and arbitrary code execution. 

There is also a type confusion vulnerability, TALOS-2024-1963 (CVE-2024-25575), that could also lead to memory corruption and arbitrary code execution. 

With RSAC just a week away, Cisco Talos is gearing up for another year of heading to San Francisco to share in some of the latest major cybersecurity announcements, research and news.  

We’ve pulled together the highlights, so you don’t miss out on all things Talos.  

Tuesday, May 7  

Joe Marshall will be presenting on Project Power Up alongside Tara Vasyliv of NPC UKRENERGO on how Talos has helped to protect Ukraine’s power grid from disruptive electronic warfare. Reserve your seat for the 8:30 a.m. session here. 

Nick Biasini will be giving a lighting talk at the Cisco Booth N-5845 in the North Hall at 3:30 p.m. on the good, the bad and the ugly of ransomware in 2024.  

Wednesday, May 8  

Nicole Hoffman will be signing her children’s book, “The Mighty Threat Intelligence Warrior,” at 12:30 p.m. in the RSA Bookstore located in Moscone South, Esplanade Level.  

Thursday, May 9  

Hoffman will be out again, this time hosting a session on applying past lessons learned in hopes of a better future for identify threat detection at 9:40 a.m. in Moscone West 3022. Reserve a seat for the session here.  

And you can always follow along all week on X and LinkedIn for the latest updates.  

If state-sponsored actors are after one thing, it’s to spread fear and uncertainty across the internet. 

There’s always money to be made targeting individual businesses and organizations, but for James Nutland’s work, it’s always about the bigger picture. And his background in studying counterterrorism and interpersonal social dynamics provides him a unique perspective on APTs’ goals and methods. 

Nutland, an analyst with Cisco Talos’ Threat Intelligence and Interdiction team, didn’t begin his journey into cybersecurity through the traditional pathways. Instead, he went to college to obtain his bachelor’s degree in social psychology, particularly interested in social engineering, eventually obtaining his master’s in counterterrorism from the University of East London. 

That may sound like a degree someone gets to serve on a physical battlefield, but as Nutland puts it, security research and counterterrorism carry some of the same throughlines. 

“It’s providing you a set of skills you can then use in multiple modalities,” he said. “It’s the analysis, the eagerness to delve into the unknown, to assess swathes of noisy information, picking out the pieces to establish different threads to try and establish patterns and hopefully attribution — it’s that kind of analytical investigative thinking that really helps for threat hunting.” 

Nutland’s technical experience comes from his undergraduate days when he started working in tech support for his college. Eventually, he got into system administration work after he moved to the U.S. during the peak of the COVID-19 pandemic.  

After various roles protecting both business and academic environments, Nutland decided to apply to Talos essentially on a whim after seeing a job listing whilst researching IOCs on the Talos intelligence center. In his current role, he conducts regular threat hunting and analysis campaigns to learn more about broader trends in the security landscape and state-sponsored threat actors. His work recently led to the disclosure of a campaign targeting Mexico users with tax-themed lure documents called “TimbreStealer,” and he participates in Cisco Talos Incident Response’s Intel-on-Demand service.  

Nutland says he goes into every engagement or new project with a completely open mind and a blank slate — using his background investigating terror operations to find out as much as he can about a particular adversary’s operation.  

“With my academic background, I’m very inquisitive. That’s proven to be a good asset,” he said. “I have a good understanding of the content and presentation of intelligence sought after in security management and operations. It’s great providing this intelligence, but providing actionable intelligence for security teams, understanding what’s required for that, it’s integral for many of the products we produce.” 

Recently, Nutland says he’s been focusing more on tracking prominent and burgeoning ransomware threat actors, as well as researching dark web activities where threat actors are leveraging obfuscated channels for their communication. Social media sites have gotten better about blocking this type of activity, he said, which has pushed them to decentralized communication platforms. He’s also tracking dark web sites that are used for obtaining ransom payments, spreading propaganda and trying to radicalize other users. 

Nutland’s work has also been crucial in Talos’ support of Ukraine during Russia’s invasion. He worked on several victim notifications for the Ukraine Task Force and discovered the malicious use of a defense evasion tool, which can wipe traces and logs of any USB devices that may have been connected to hardware and certain user activity on the host.  

“I initially saw a suspicious specific set of commands that were being run related to the executable, that I was able to track across multiple potential Ukrainian victims which Ukrainian organizations are now looking to crack down on,” Nutland said. 

In all his roles so far in his career, Nutland said he’s experienced various forms of imposter syndrome throughout his career, as many do. He said he often found himself questioning decisions, or feeling like other teammates were more qualified for his role. But at Talos, his managers have encouraged him to turn over every rock and go into every situation, curious and open. That’s allowed him to overcome that imposter syndrome and become a sponge, learning everything he could about a particular topic and becoming an expert in his own right. 

This culminated in a presentation to more than 300 people at the MITRE ATT&CKcon 4.0 in October, where he and his teammate, Nicole Hoffman, gave a talk about how threat actors can use the ATT&CK framework to track adversary activity. 

“Here are these titans of threat intelligence at a world-renowned convention. And here’s me, recently employed at Talos, and with incredible imposter syndrome,” Nutland said. “But there were about 300 people in the room, and Nicole and I knocked it out of the park. I never thought I’d be doing that.” 

Outside of the office, Nutland enjoys playing rugby, and he even was recently able to play a scrimmage against the Colombian National Team, a particular highlight for his career outside of cybersecurity. 

I wrote last week about the problems arising from the massive backlog of vulnerabilities at the U.S. National Vulnerability Database.  

Thousands of CVEs are still without analysis data, and the once-reliable database of every single vulnerability that’s disclosed and/or patched is now so far behind, it could take up to 100 days for the National Institute of Standards and Technology (NIST) to catch up, and that would be assuming no new vulnerabilities are disclosed during that period. 

While the U.S. government and NIST try to sort out a potential solution, and hopefully await more funding and restructuring, NIST says it’s hoping to launch a consortium to help either rebuild the NVD or create a replacement.  

Other security experts have floated the idea of other companies or organizations creating a brand-new solution of their own. The main problem with that is, what’s in it for them?  

What works about the NVD is that it’s funded by the U.S. government, so the money is always coming in to help fund the workforce and at least gives MITRE and the other private companies who contribute to the NVD motivation to keep working on it. 

To start up a whole new database of *every* CVE out there would take countless man-hours, and then what at the end? Would the company or person(s) who created it start charging for access? 

Several open-source solutions haveman-hours popped up over the past few weeks, such as “NVD Data Overrides,” which “is meant to provide additional data that is currently missing from NVD.” However, these types of volunteer projects still can’t assign CVSS scores, because only the NVD is authorized to hand out official NVD CVSS scores. 

This brings up another problem for private companies that may want to develop a solution: Do they want to play referee?  

Sometimes, when there’s a disagreement on how severe a vulnerability is and what severity score to assign it, the NVD will weigh in and provide their own, independently calculated CVSS score. Who really wants to be the “bad guy” to get between a massive tech company like Microsoft or Apple and a security researcher saying a vulnerability is a 9.5 out of 10 CVSS? 

I absolutely give major credit to any volunteers or open-source developers who are working on their own solutions for essentially nothing — but how long can we expect them to keep maintaining these databases? 

Unfortunately, I don’t have a great answer for this, either. I’m far from an expert on vulnerability management, nor do I have any connections to the federal government. But I do feel the onus is on the government to come up with a solution, and potentially provide incentives for companies and researchers to participate in this new proposed consortium because I don’t see the incentives there for the private sector to come up with their own solution.  

The one big thing 

ArcaneDoor is a new campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Talos and Cisco PSIRT recently identified a previously unknown actor, now tracked as UAT4356 by Talos and STORM-1849 by the Microsoft Threat Intelligence Center. This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor. UAT4356 deployed two backdoors as components of this campaign, “Line Runner” and “Line Dancer,” which were used collectively to conduct malicious actions on-target, which included configuration modification, reconnaissance, network traffic capture/exfiltration and potentially lateral movement.   

Why do I care? 

Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications. In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations — critical infrastructure entities that are likely strategic targets of interest for many foreign governments. As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective. 

So now what? 

There are some known indicators of compromise that customers can look for if they suspect they may have been targeted in this campaign. First, organizations should look for any flows to/from ASA devices to any of the IP addresses present in the IOC list provided at the bottom of this blog. This is one indication that further investigation is necessary. Potential targets can also follow the steps detailed in the Cisco ASA Forensic Investigation Procedures for First Responders. When following these procedures, first responders should NOT attempt to collect a core dump or reboot the device if they believe that the device has been compromised, based on the lina memory region output. Talos also released some Snort signatures to detect the activity on the wire including access attempts. Snort Signatures 63139, 62949 and 45575 have been released to detect the implants or associated behaviors. 

Top security headlines of the week 

A previously known Windows print spooler bug is still being actively exploited, according to Microsoft. The company’s threat research team recently disclosed that APT28, a well-known Russian state-sponsored actor, is exploiting the vulnerability to deliver a previously unknown malware called “GooseEgg.” Microsoft disclosed and patched CVE-2022-38028 in October 2022, but APT28 may have been exploiting it as far back as 2020. The actor’s exploitation involved modifying a JavaScript constraints file in the printer spooler and executing it with SYSTEM-level permissions. The new research prompted the U.S. Cybersecurity and Infrastructure Security Agency (CISA) to add CVE-2022-38028 to its Known Exploited Vulnerabilities (KEV) catalog. If installed, GooseEgg can load other applications with System-level permissions and allow the adversary to execute remote code on the targeted device or deploy other backdoors. Another set of print spooler vulnerabilities, called PrintNightmare, made headlines in July 2021, though no one reported active exploitation of that vulnerability at the time. (SC Magazine, Security Week) 

A new investigation revealed how members of the group Scattered Spider are partnering with Russian state-sponsored actors to carry out ransomware attacks. Scattered Spider is made up of younger individuals based out of the U.S., U.K. and Canada. They are primarily English speakers who have been blamed for several notable ransomware attacks, including one against MGM Casinos that disrupted operations at several casinos and hotels last year. The group specializes in social engineering, more recently using LinkedIn to steal employee information and use that to infiltrate corporate networks. Members, some as young as teenagers, are connecting over the dark web and online forums like Discord and use their advanced knowledge of Western civilization to provide crucial details to Russian actors. The “60 Minutes” investigation also included new details about The Community (aka “The Comm,” the online collection of hackers who like to brag about their recent cybercrimes, often through Telegram. (CBS News) 

The U.S. government has re-upped a law that expands government surveillance by opening the door for private companies to partner with the government on these types of activities. The controversial Foreign Intelligence Surveillance Act (FISA) was re-approved just hours after it lapsed. The White House and proponents in U.S. Congress argued that the powers granted in Section 702 of the FISA helps prevent the spread of terrorism and cyber attacks and that any lapse in those powers would harm the government’s ability to gather crucial intelligence. However, privacy advocates say that the FISA is an overreach, and provides too much power for private companies to potentially spy on consumers. The bill also includes a new definition of “electronic communications service provider,” which could allow the U.S. government to force Big Tech companies and telecommunications providers to hand over users’ data if requested. (NBC News, TechCrunch) 

Can’t get enough Talos? 

• Talos Takes Ep. #180: What are the dangers of enabling sideloading and third-party apps? 
• Suspected CoralRaider continues to expand victimology using three information stealers 
• Brute-force attacks surge worldwide, warns Cisco Talos    
• Cisco Warns of Massive Surge in Password-Spraying Attacks on VPNs 
• Rare Computer Virus Detected in Ukrainian Network, Confidential Document Potentially Compromised 

Upcoming events where you can find Talos 

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Cisco Live (June 2 - 6) 

Las Vegas, Nevada  

Most prevalent malware files from Talos telemetry over the past week 

This section will be on a brief hiatus while we work through some technical difficulties. Several open-source solutions have

Business email compromise (BEC) was the top threat observed by Cisco Talos Incident Response (Talos IR) in the first quarter of 2024, accounting for nearly half of engagements, which is more than double what was observed in the previous quarter.  

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, which accounted for 29 percent of engagements. The high number of BEC attacks likely played a significant role in valid accounts being the top attack vector this quarter. Weaknesses involving multi-factor authentication (MFA) were observed within nearly half of engagements this quarter, with the top observed weakness being users accepting unauthorized push notifications, occurring within 25 percent of engagements.  

There was a slight decrease in ransomware this quarter, accounting for 17 percent of engagements. Talos IR responded to new variants of Phobos and Akira ransomware for the first time this quarter. 

Manufacturing was the most targeted vertical this quarter, closely followed by education, a continuation from Q4 2024 where manufacturing and education were also two of the most targeted verticals. There was a 20 percent increase in manufacturing engagements from the previous quarter. 

The manufacturing sector faces unique challenges due to its inherently low tolerance for operational downtime. This quarter, Talos IR observed a wide range of threat activity targeting manufacturing organizations including financially motivated attacks, such as BEC and ransomware, and some brute force activity targeting virtual private network (VPN) infrastructure. The use of compromised credentials on valid accounts was the top observed attack vector within attacks targeting the manufacturing sector this quarter, which represents a change from the previous quarter when the top attack vector observed in these types of engagements was exploiting vulnerabilities in public-facing applications.   

Watch discussion on the report's biggest trends

Surge in BEC 

Within BEC attacks, adversaries will send phishing emails appearing to be from a known or reputable source making a valid request, such as updating payroll direct deposit information. BEC attacks can have many motivations, often financially driven, aimed at tricking organizations into transferring funds or sensitive information to malicious actors.  

BEC offers adversaries the advantage of impersonating trusted contacts to facilitate internal spearphishing attacks that can bypass traditional external defenses and increase the likelihood of deception, widespread malware infections and data theft. 

In one engagement, adversaries performed a password-spraying attack and MFA exhaustion attacks against several employee accounts. There was a lack of proper MFA implementation across all the impacted accounts, leading to the adversaries gaining access to at least two accounts using single-factor authentication. The organization detected and disrupted the attack before adversaries could further their access or perform additional post-compromise activities.    

In another cluster of activity, several employees received spear-phishing emails that contained links that, when clicked, led to a redirection chain of web pages ultimately landing on a legitimate single sign-on (SSO) prompt that was pre-populated with each victim’s email address. The attack was unsuccessful because none of the employees interacted with the email, which was likely due to multiple red flags. For example, the email was unexpected and sent from an external email address, and there was small text within the email that referred to the email as a fax, which was all indicators of a phishing attempt. 

Ransomware trends 

Ransomware accounted for 17 percent of engagements this quarter, an 11 percent decrease from the previous quarter. Talos IR observed new variants of Akira and Phobos ransomware for the first time this quarter. 

Akira 

Talos IR responded to an Akira ransomware attack for the first time this quarter in an engagement where affiliates deployed the latest ESXi version, “Akira_v2,” as well as a Windows-based variant of Akira named “Megazord.” These new Akira variants are written in the Rust programming language, which is a notable change from the previously used C++ and Crypto++ programming languages.  

Talos IR could not determine how initial access was gained, which is common because ransomware attacks often involve multi-stage attack strategies that add additional complexity during the investigation process. Once inside the network, the adversaries began collecting credentials from the memory of the Local Security Authority Subsystem Service (LSASS) and the New Technology Directory Services Directory Information Tree (NTDS.dit) database, where Active Directory data is stored, and leveraged Remote Desktop Protocol (RDP) for lateral movement. Prior to encryption, Megazord ransomware began executing several commands to disable tools and impair defenses, including “net stop” and “taskkill.” Akira_v2 appended the file extension “.akiranew” during encryption, while Megazord ransomware appended the file extension “.powerranges”.   

First discovered in early 2023, Akira operates as a ransomware-as-a-service (RaaS) model and employs a double extortion scheme that involves exfiltrating data before encryption. Akira affiliates are known to heavily target small- to medium-sized businesses within several verticals primarily located within the U.S. but have targeted organizations within the U.K., Canada, Iceland, Australia and South Korea. Akira affiliates are notorious for leveraging compromised credentials and exploiting vulnerabilities as a means of gaining initial access, such as the SQL injection vulnerability, tracked as CVE-2021-27876, affecting certain versions of Zoho ManageEngine ADSelfService Plus, and the vulnerability, tracked as CVE-2023-27532, affecting certain versions of Veeam’s Backup & Replication (VBS) software.    

Phobos 

Talos IR has previously observed variants of Phobos ransomware, such as “Faust,” but this quarter, Talos IR responded to an engagement with the “BackMyData” variant of Phobos ransomware. The adversaries leveraged Mimikatz to dump credentials from Active Directory. The adversary also installed several tools in the NirSoft product suite designed to recover passwords, such as PasswordFox and ChromePass, for additional credential enumeration. 

The adversaries used PsExec to access the domain controller before setting a registry key to permit remote desktop connections. Shortly after, the adversaries also modified the firewall to allow remote desktop connections using the Windows scripting utility, netsh. The remote access tool AnyDesk was downloaded to enable remote access as a means of persistence in the environment. Talos IR assessed with high confidence that Windows Secure Copy (WinSCP) and Secure Shell (SSH) were likely used to exfiltrate staged data. Adversaries also relied on PsExec to execute commands, such as deleting volume shadow copies, as a precursor to deploying the ransomware executable. After encryption, the ransomware appended the file extension “.fastbackdata”.   

A notable finding was the persistent use of the “Users/[username]/Music” directory as a staging area for data exfiltration to host malicious scripts, tools and malware, a common technique used by numerous ransomware affiliates to evade detection and remain persistent in the environment. Talos IR also identified a digitally signed executable, “HRSword,” developed by Beijing Huorong Network Technology. It is a tool the affiliate used during the attack for potential secure file deletion and as a defensive measure to disable endpoint protection tools, which Phobos affiliates were previously using, according to public reporting.   

Phobos ransomware first emerged in late 2018 and shared many similarities with the Crysis and Dharma ransomware families. Unlike other ransomware families, there are many variants of Phobos ransomware, such as Eking, Eight, Elbie, Devos and Faust. There is little information known about the business model leveraged by the Phobos ransomware operation. In November 2023, Cisco Talos analyzed over a thousand samples of Phobos ransomware to learn more about the affiliate structure and activity, which revealed that Phobos may operate a RaaS model due to the hundreds of contact emails and IDs associated with Phobos campaigns, indicating the malware has a dispersed affiliate base. Talos assessed with moderate confidence that the Phobos ransomware operation is actively managed by a central authority, as there is only one private key capable of decryption in all observed campaigns. 

Other observed threats  

Talos IR responded to an attack where adversaries were attempting to brute force several Cisco Adaptive Security Appliances (ASAs). Although the adversaries were unsuccessful in their attack, this activity is in line with the recently observed trend affecting VPN services. 

Cisco Talos has recently seen an increase in malicious activity targeting VPN services, web application authentication interfaces, and Secure Shell (SSH) globally. Since at least March 18, Cisco has observed scanning and brute force activity sourcing from The Onion Router (TOR) exit nodes and other anonymous tunnels and proxies. 

Depending on the target environment, a successful attack could result in unauthorized access to a target network, possibly leading to account lockouts and denial-of-service (DoS) conditions. The brute force attempts include a combination of generic usernames and valid usernames unique to specific organizations. The activity seems indiscriminate and has been observed across multiple industry verticals and geographic regions. 

Initial vectors 

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, accounting for 29 percent of engagements, a continuation of a trend from the previous quarter when valid accounts were also a top attack vector. 

Security weaknesses 

For the first time, users accepting unauthorized MFA push notifications was the top observed security weakness, accounting for 25 percent of engagements this quarter. The lack of proper MFA implementation closely followed, accounting for 21 percent of engagements, a 44 percent decrease from the previous quarter. 

Users must have a clear understanding of the appropriate business response protocols when their devices are overwhelmed with an excessive volume of push notifications. Talos IR recommends organizations educate their employees about the specific channels and points of contact for reporting these incidents. Prompt and accurate reporting enables security teams to quickly identify the nature of the issue and implement the necessary measures to address the situation effectively. Organizations should also consider implementing number-matching in MFA applications to provide an additional layer of security to prevent users from accepting malicious MFA push notifications. 

Talos IR recommends implementing MFA on all critical services including all remote access and identity access management (IAM) services. MFA will be the most effective method for the prevention of remote-based compromises. It also prevents lateral movement by requiring all administrative users to provide a second form of authentication. Organizations can set up alerting for single-factor authentication to quickly identify potential gaps. 

Top observed MITRE ATT&CK techniques 

The table below represents the MITRE ATT&CK techniques observed in this quarter’s IR engagements and includes relevant examples and the number of times seen. Given that some techniques can fall under multiple tactics, we grouped them under the most relevant tactic based on the way they were leveraged. Please note, this is not an exhaustive list. 

Key findings from the MITRE ATT&CK framework include:  

• Remote access software, such as SplashTop and AnyDesk, were used in 17 percent of engagements this quarter, a 20 percent decrease from the previous quarter.  
• The use of email hiding rules was the top observed defense evasion technique, accounting for 21 percent of engagements this quarter.   
• Scheduled tasks were leveraged by adversaries the most this quarter for persistence, accounting for 17 percent of engagements this quarter, a 33 percent increase from the previous quarter.  
• The abuse of remote services, such as RDP, SSH, SMB and WinRM, more than doubled this quarter compared to the previous quarter, accounting for nearly 60 percent of engagements. 

*Updated 2024-04-25 16:57 GMT with minor wording corrections regarding the targeting of other vendors.

ArcaneDoor is a campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Coveted by these actors, perimeter network devices are the perfect intrusion point for espionage-focused campaigns. As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective. Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications. In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations — critical infrastructure entities that are likely strategic targets of interest for many foreign governments.  

Cisco’s position as a leading global network infrastructure vendor gives Talos’ Intelligence and Interdiction team immense visibility into the general state of network hygiene. This also gives us uniquely positioned investigative capability into attacks of this nature. Early in 2024, a vigilant customer reached out to both Cisco’s Product Security Incident Response Team (PSIRT) and Cisco Talos to discuss security concerns with their Cisco Adaptive Security Appliances (ASA). PSIRT and Talos came together to launch an investigation to assist the customer. During that investigation, which eventually included several external intelligence partners and spanned several months, we identified a previously unknown actor now tracked as UAT4356 by Talos and STORM-1849 by the Microsoft Threat Intelligence Center. This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor. 

UAT4356 deployed two backdoors as components of this campaign, “Line Runner” and “Line Dancer,” which were used collectively to conduct malicious actions on-target, which included configuration modification, reconnaissance, network traffic capture/exfiltration and potentially lateral movement.  

Critical Fixes Available 

Working with victims and intelligence partners, Cisco uncovered a sophisticated attack chain that was used to implant custom malware and execute commands across a small set of customers. While we have been unable to identify the initial attack vector, we have identified two vulnerabilities (CVE-2024-20353 and CVE-2024-20359), which we detail below. Customers are strongly advised to follow the guidance published in the security advisories discussed below.  

Further, network telemetry and information from intelligence partners indicate the actor is interested in — and potentially attacking — Microsoft Exchange servers and network devices from other vendors. Regardless of your network equipment provider, now is the time to ensure that the devices are properly patched, logging to a central, secure location, and are configured to have strong, multi-factor authentication (MFA). Additional recommendations specific to Cisco are available here.  

Timeline 

Cisco was initially alerted to suspicious activity on an ASA device in early 2024. The investigation that followed identified additional victims, all of which involved government networks globally. During the investigation, we identified actor-controlled infrastructure dating back to early November 2023, with most activity taking place between December 2023 and early January 2024. Further, we have identified evidence that suggests this capability was being tested and developed as early as July 2023.   

Cisco has identified two vulnerabilities that were abused in this campaign (CVE-2024-20353 and CVE-2024-20359). Patches for these vulnerabilities are detailed in the Cisco Security Advisories released today.

Initial Access 

We have not determined the initial access vector used in this campaign. We have not identified evidence of pre-authentication exploitation to date. Our investigation is ongoing, and we will provide updates, if necessary, in the security advisories or on this blog.

Line Dancer: In-Memory Implant Technical Details 

The malware implant has a couple of key components. The first is a memory-only implant, called “Line Dancer.” This implant is a memory-resident shellcode interpreter that enables adversaries to upload and execute arbitrary shellcode payloads.  

On a compromised ASA, the attackers submit shellcode via the host-scan-reply field, which is then parsed by the Line Dancer implant. Note that the use of this field does not indicate the exploitation of CVE-2018-0101 which was NOT used as a component of this campaign. The host-scan-reply field, typically used in later parts of the SSL VPN session establishment process, is processed by ASA devices configured for SSL VPN, IPsec IKEv2 VPN with “client-services" or HTTPS management access. The actor overrides the pointer to the default host-scan-reply code to instead point to the Line Dancer shellcode interpreter. This allows the actor to use POST requests to interact with the device without having to authenticate and interact directly through any traditional management interfaces. 

Line Dancer is used to execute commands on the compromised device. During our investigation, Talos was able to observe the threat actors using the Line Dancer malware implant to: 

• Disable syslog. 
• Run and exfiltrate the command show configuration. 
• Create and exfiltrate packet captures. 
• Execute CLI commands present in shellcode; this includes configuration mode commands and the ability to save them to memory (write mem). 
• Hook the crash dump process, which forces the device to skip the crash dump generation and jump directly to a device reboot. This is designed to evade forensic analysis, as the crash dump would contain evidence of compromise and provide additional forensic details to investigators. 
• Hook the AAA (Authentication, Authorization and Accounting) function to allow for a magic number authentication capability. When the attacker attempts to connect to the device using this magic number, they are able to establish a remote access VPN tunnel bypassing the configured AAA mechanisms. As an alternate form of access, a P12 blob is generated along with an associated certificate and exfiltrated to the actor along with a certificate-based tunnel configuration.  

Host-Scan-Reply hook overview 

In the Line Dancer implant’s process memory, we found a function (detailed below) that checks if a 32-byte token matches a pattern. If so, it base64-decodes the payload, copies it into the attacker's writable and executable memory region, and then calls the newly decoded function. Either way, it ends by calling processHostScanReply(). 

The function processHostScanReply() is normally accessed through a function pointer in the elementArray table, associated with the string host-scan-reply. In the captured memory, the entry that should point to processHostScanReply() now instead points to the attacker's function that decodes and runs its payload. Since this change is in the data section of memory, it doesn't show up in hashes/dumps of text. 
 
The attacker function that decodes and runs its payload has the following decompilation: 

Line Runner: Persistence Mechanism 

The threat actor maintains persistence utilizing a second, but persistent, backdoor called “Line Runner” on the compromised ASA device using functionality related to a legacy capability that allowed for the pre-loading of VPN clients and plugins on the device. At boot, the ASA is designed to look for the presence of a file on disk0: matching the Lua regular expression:

 ^client_bundle[%w_-]*%.zip$  

If the file exists, it will unzip it and execute the script csco_config.lua. Once processed, the ZIP file is deleted. This is assigned CVE-2024-20359 and more details are available in this Cisco Security Advisory.  

In at least one case, there is another vulnerability, CVE-2024-20353, that was abused by the actor to facilitate this process. The attackers were able to leverage this vulnerability to cause the target ASA device to reboot, triggering the unzipping and installing the second component of the threat actor’s malware implant, Line Runner. 

The threat actor’s ZIP file has the following files: 

The scripts in the zip file allow the threat actor to maintain a persistent HTTP-based Lua backdoor to the ASA, which survives across reboots and upgrades. Line Runner was observed being used by UAT4356 to retrieve information that was staged through the use of Line Dancer.  

csco_config.lua 

The csco_config.lua file is run at boot and makes the following modifications to the system: 
 
• Create disk0:/csco_config/97/webcontent/ if it doesn't already exist 
• Create disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098 from hash.txt 
• Append index.txt to disk0:/csco_config/97/webcontent/index_bp.ini and put the result in disk0:/csco_config/97/webcontent/index.ini 
• Move the original client_bundle.zip file to /run/lock/subsys/krbkdc6
• Prepend umtfc.txt to /etc/init.d/umountfs 
• Copy stgvdr.txt to /asa/scripts/lina_cs 
• Backup /asa/scripts/lina_exe_cs.sh to /asa/scripts/lina_exe_cs_bp.sh 
• Replace /asa/scripts/lina_exe_cs.sh with laecsnw.txt 
• Copy csco_config2.lua over csco_config.lua 
• Disable the importPlugin function for the next call only  

csco_config2.lua 

The csco_config2.lua file cleans up the modifications made by csco_config.lua (above) and removes itself. 

hash.txt 

Used as content for disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098. 

Intercepts HTTP requests to the ASA. The threat actor’s code looks for an HTTP request with a set of 32-character parameters that are victim-dependent. If they match, then the payload contained within one of these parameters is written to a Lua script and executed. This is the backdoor’s command and control mechanism. 

index.txt 

Adds webContent information so hash.txt is processed. 

laecsnw.txt 

Temporarily replaces /asa/scripts/lina_exe_cs.sh. 

Executes /asa/scripts/lina_cs as a background process (see below). Removes itself. Then restore the backup /asa/scripts/lina_exe_cs_bp.sh.  

stgvdr.txt 

Runs as /asa/scripts/lina_cs. 

After sleeping for 30 seconds, sets expected owner and times on /etc/init.d/umountfs. Removes the hash API endpoint, the index.ini, and either restores the backup index.ini or removes the webcontent directory entirely. Finally, removes itself.  

umtfc.txt

Prepended to /etc/init.d/unmountfs. 

The unmountfs script is called at shutdown to unmount the filesystems. The threat actor’s modifications perform the following functionality: 

• If disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098 exists, it removes it and index.ini. 
• Copy /run/lock/subsys/krbkdc6 to disk0:client_bundle_install.zip

This sets up the zipfile to be executed at the next boot, maintaining persistence. 

Forensic Recovery and Identification of Line Runner 

To identify the presence of Line Runner on an ASA, the following methods can be used. Note also that the device should be upgraded to a fixed version as identified in the first method. 

Method 1: 

After updating the device to a software release that contains the fix for CVE-2024-20359, a review of the contents of disk0: should be conducted. If a new file (e.g., “client_bundle_install.zip” or any other unusual .zip file) appears on disk0: following the update, this suggests that Line Runner was present on the device in question. Note that because the updated software is not vulnerable to CVE-2024-20359, Line Runner will no longer be active on the device. 

Method 2: 

To detect (and remove) Line Runner, the following series of commands will create an innocuous file with a .zip extension. Note that it will not create a valid zip file, but the file will still be read by the ASA at reboot. Upon execution of the following commands, if a new .zip file appears on disk0: following the reload, this suggests that Line Runner was present on the device in question. Deletion of the “client_bundle_install.zip” file will remove Line Runner. Note that the malicious ZIP containing the Line Runner functionality could have other names that fit the naming pattern outlined previously.  

If you discover a newly created .zip file, copy that file off the device using the copy command and contact [email protected] referencing CVE-2024-20359. Include the outputs of the dir disk0: and show version commands from the device and the .zip file extracted from the device. 

Anti-Forensics/Anti-Analysis Capabilities 

UAT4356 took clear and deliberate steps to attempt to prevent forensic capture of malicious artifacts. This tradecraft suggests a thorough understanding of the ASA itself and of the forensic actions commonly performed by Cisco for network device integrity validation. Additional steps were taken on a case-by-case basis to hide actions being taken on the device. These steps included hooking the AAA (Authentication, Authorization and Accounting) function of the device to allow the actor to bypass normal AAA operations. We also identified some instances where UAT4356 disabled logging to perform operations on or from the ASA and not have those operations or actions logged.  

Line Dancer appears to have been intentionally placed into a difficult-to-reach region of memory. In addition, it hooks into functions such as the core dump function, which is commonly used to collect information for debugging and forensic purposes, which were made in memory such that this function simply jumped to a reboot. This means that on reboot, Line Dancer itself would no longer be present and none of the collections present in the core dump function would have been executed, all resulting in a complete loss of debug information and memory-based forensic artifacts. 

Attribution  

As a part of our ongoing investigation, we have also conducted analysis on possible attribution of this activity. Our attribution assessment is based on the victimology, the significant level of tradecraft employed in terms of capability development and anti-forensic measures, and the identification and subsequent chaining together of 0-day vulnerabilities. For these reasons, we assess with high confidence that these actions were performed by a state-sponsored actor.

Recommendations 

There are some known indicators of compromise that customers can look for if they suspect they may have been targeted in this campaign. First, organizations should look for any flows to/from ASA devices to any of the IP addresses present in the IOC list provided at the bottom of this blog. This is one indication that further investigation is necessary. 

Additionally, organizations can issue the command show memory region | include lina to identify another indicator of compromise. If the output indicates more than one executable memory region (memory regions having r-xp permissions, see output examples), especially if one of these memory sections is exactly 0x1000 bytes, then this is a sign of potential tampering.   

Note that the earlier provided steps to identify the presence of Line Runner can still be followed even in the absence of more than one executable memory region as we have seen cases where Line Runner was present without Line Dancer being present. We still recommend following the steps to upgrade to a patched version even if customers believe that their device has not been compromised.  

Next, follow the steps detailed in the Cisco ASA Forensic Investigation Procedures for First Responders. When following these procedures first responders should NOT attempt to collect a core dump (Step 5) or reboot the device if they believe that the device has been compromised, based on the lina memory region output. The previous steps up to and including a collection of the memory text section should be followed. In addition, we have released some Snort signatures to detect the activity on the wire including access attempts. Signatures 63139, 62949, and 45575 have been released to detect the implants or associated behaviors. Please note that the device must be set up to decrypt TLS for these signatures to be effective. 

• CVE-2024-20353 (ASA DOS/Reboot) - 3:63139 
• ‘Line Runner’ – Persistence Mechanism Interaction – 3:62949 
• ‘Line Dancer’ – In-Memory Only Shellcode Interpreter Interaction – 3:45575 
• Note that this signature was originally built to detect an unrelated CVE but it also detects Line Dancer interaction 

If your organization does find connections to the provided actor IPs and the crash dump functionality has been altered, please open a case with Cisco TAC.  

UAT4356 Infrastructure 

Key components of the actor-controlled infrastructure used for this operation had an interesting overlap of SSL certificates which match the below pattern while also appearing as an ASA, during the same period, to external scanning engines such as Shodan and Censys as reported by the CPE data on the same port as the noted SSL certificate. The SSL certificate information suggests that the infrastructure is making use of an OpenConnect VPN Server (https://ocserv.openconnect-vpn.net) through which the actor appeared to be conducting actions on target. 

Certificate Pattern: 
:issuer = O=ocserv,CN=ocserv VPN 
:selfsigned = true 
:serial = 0000000000000000000000000000000000000002 
:subject = O=ocserv,CN=ocserv VPN 
:version = v3 

CPE identifiers:  
cpe:2.3:a:cisco:http:*:*:*:*:*:*::
cpe:2.3:h:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* 
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* 

MITRE TTPs 

This  threat demonstrates several techniques of the MITRE ATT&CK framework, most notably: 

• Line Runner persistence mechanism (T1037),  
• The reboot action via CVE-2024-20353 (T1653),  
• Base64 obfuscation (T1140),  
• Hooking of the processHostScanReply() function (T0874),  
• Disabling syslog and tampering with AAA (T1562-001), 
• Injection of code into AAA and Crash Dump processes (T1055)  
• Execution of CLI commands (T1059),  
• Bypassing of the AAA mechanism (T1556),  
• Removal of files after execution (T1070-004),  
• HTTP interception for C2 communications (T1557),  
• HTTP C2 (T1071-001),  
• HTTP C2 one-way backdoor (T1102-003),  
• Data exfiltration over C2 (T1041),  
• Network sniffing (T1040)  

Coverage 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Umbrella, Cisco's secure internet gateway (SIG) blocks devices from connecting to malicious IPs. Sign up for a free trial of Umbrella here. 

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center. 

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SIDs for this threat are 45575, 62949 and 63139. 

Indicators of Compromise (IOCs)  

There are several known indicators of compromise that defenders can look for when assessing whether their ASA device has been compromised as a result of this attack, as outlined earlier in this post. For example, if any gaps in logging or any recent unexpected reboots are observed, this should be treated as suspicious activity that warrants further investigation. Also, below is a list of IP addresses we identified as having been used by UAT4356. Please note that some of these IPs are part of publicly known anonymization infrastructure and not directly controlled by the attackers themselves. If your organization does find connections to the provided actor IPs and the crash dump functionality has been altered, please open a case with Cisco TAC. 

Likely Actor-Controlled Infrastructure: 

192.36.57[.]181 
185.167.60[.]85 
185.227.111[.]17 
176.31.18[.]153 
172.105.90[.]154 
185.244.210[.]120 
45.86.163[.]224 
172.105.94[.]93 
213.156.138[.]77 
89.44.198[.]189 
45.77.52[.]253 
103.114.200[.]230 
212.193.2[.]48 
51.15.145[.]37 
89.44.198[.]196 
131.196.252[.]148 
213.156.138[.]78 
121.227.168[.]69 
213.156.138[.]68 
194.4.49[.]6 
185.244.210[.]65 
216.238.75[.]155  

Multi-Tenant Infrastructure: 

5.183.95[.]95 
45.63.119[.]131 
45.76.118[.]87 
45.77.54[.]14 
45.86.163[.]244 
45.128.134[.]189    
89.44.198[.]16 
96.44.159[.]46 
103.20.222[.]218 
103.27.132[.]69 
103.51.140[.]101 
103.119.3[.]230 
103.125.218[.]198 
104.156.232[.]22 
107.148.19[.]88 
107.172.16[.]208 
107.173.140[.]111 
121.37.174[.]139 
139.162.135[.]12 
149.28.166[.]244 
152.70.83[.]47 
154.22.235[.]13 
154.22.235[.]17 
154.39.142[.]47  
172.233.245[.]241 
185.123.101[.]250 
192.210.137[.]35  
194.32.78[.]183 
205.234.232[.]196  
207.148.74[.]250 
216.155.157[.]136 
216.238.66[.]251 
216.238.71[.]49 
216.238.72[.]201 
216.238.74[.]95 
216.238.81[.]149 
216.238.85[.]220 
216.238.86[.]24  

Acknowledgments  

Cisco would like to thank the following organizations for supporting this investigation: 

• Australian Signals Directorate’s Australian Cyber Security Centre 
• Black Lotus Labs at Lumen Technologies 
• Canadian Centre for Cyber Security, a part of the Communications Security Establishment 
• Microsoft Threat Intelligence Center 
• The UK's National Cyber Security Centre (NCSC) 
• U.S. Cybersecurity & Infrastructure Security Agency (CISA) 

By Joey Chen, Chetan Raghuprasad and Alex Karkins. 

• Cisco Talos discovered a new ongoing campaign since at least February 2024, operated by a threat actor distributing three famous infostealer malware, including Cryptbot, LummaC2 and Rhadamanthys.
• Talos also discovered a new PowerShell command-line argument embedded in the LNK file to bypass anti-virus products and download the final payload into the victims’ host.
• This campaign uses the Content Delivery Network (CDN) cache domain as a download server, hosting the malicious HTA file and payload. 
• Talos assesses with moderate confidence that the threat actor CoralRaider operates the campaign. We observed several overlaps in tactics, techniques, and procedures (TTPs) of CoralRaider’s Rotbot campaign, including the initial attack vector of the Windows Shortcut file, intermediate PowerShell decryptor and payload download scripts, the FoDHelper technique used to bypass User Access Controls (UAC) of the victim machine.  

Victimology and actor infrastructure

The campaign affects victims across multiple countries, including the U.S., Nigeria, Pakistan, Ecuador, Germany, Egypt, the U.K., Poland, the Philippines, Norway, Japan, Syria and Turkey, based on our telemetry data and OSINT information. Our telemetry also disclosed that some affected users were from Japan’s computer service call center organizations and civil defense service organizations in Syria. The affected users were downloading files masquerading as movie files through the browser, indicating the possibility of a widespread attack on users across various business verticals and geographies.

We observe that this threat actor is using a Content Delivery Network (CDN) cache to store the malicious files on their network edge host in this campaign, avoiding request delay. The actor is using the CDN cache as a download server to deceive network defenders. 

Talos discovered that the actor is using multiple C2 domains in the campaign. The DNS requests for the domains during our analysis period are shown in the graph, indicating the campaign is ongoing. 

Tactics, techniques and procedures overlap with other campaigns 

Talos assesses with moderate confidence that threat actor CoralRaider is likely operating this campaign based on several overlaps in the TTPs used and the targeted victims’ geography of this campaign with that of the CoralRaider’s Rotbot campaign. We spotted that the PowerShell scripts used in the attack chain of this campaign to decrypt the PowerShell scripts of further stages and the downloader PowerShell script are similar to those employed in the Rotbot’s campaign.

The Powershell script did not appear in any public repository or article, indicating the threat actor likely developed these PowerShell scripts. Pivoting on the PowerShell argument embedded in the LNK file showed us that such arguments are not popular and likely specific to the actor and the campaign.  

Multi-stage infection chain to deliver the payload 

The infection chain starts when a victim opens the malicious shortcut file from a ZIP file downloaded using the drive-by download technique, according to our telemetry. The threat actor is likely delivering malicious links to victims through phishing emails.

The Windows shortcut file has an embedded PowerShell command running a malicious HTA file on attacker-controlled CDN domains. HTA file executes an embedded Javascript, which decodes and runs a PowerShell decrypter script. PowerShell decrypter script decrypts the embedded PowerShell Loader script and runs it in the victim’s memory. The PowerShell Loader executes multiple functions to evade the detections and bypass UAC, and finally, it downloads and runs one of the payloads, Cryptbot, LummaC2 or Rhadamanthys information stealer.

Windows Shortcut file to execute the malicious HTA file

Windows shortcut file runs a PowerShell command to download and run an HTML application file on the victim’s machine. The threat actor has used “gp,” a PowerShell command alias for Get-ItemProperty, to read the registry contents of the application classes registry key and gets the executable name “mshta.exe.” Using mshta.exe, the PowerShell instance executes the remotely hosted malicious HTA file on the victim’s machine. 

Obfuscated HTA runs embedded PowerShell decrypter  

The malicious HTML application file is heavily obfuscated and has a Javascript that decodes and executes a function using the String fromCharCode method. The decoded function then executes an embedded PowerShell decryptor script. 

The decryptor PowerShell script has a block of AES-encrypted string. Using the AES decryptor function, it generates an AES key of 256 bytes from a base64 encoded string “RVRVd2h4RUJHUWNiTEZpbkN5SXhzUWRHeFN4V053THQ=” and the IV “AAAAAAAAAAAAAAAA.” With the key and IV, it decrypts and executes the next stage of the PowerShell Loader script. 

PowerShell loader downloads and runs the payload

The PowerShell loader script is modular and has multiple functions to perform a sequence of activities on the victim’s machine. Initially, it executes a function that drops a batch script in the victim machine’s temporary folder and writes its contents, which includes the PowerShell command to add the folder “ProgramData” of the victim machine to the Windows Defender exclusion list. 

The dropped bath script is executed through a living-off-the-land binary (LoLBin) “FoDHelper.exe” and a Programmatic Identifiers (ProgIDs) registry key to bypass the User Access Controls (UAC) in the victim’s machine. Fodhelper is a Windows feature, an on-demand helper binary that runs by default with high integrity. Usually, when the FodHelper is run, it checks for the presence of the registry keys listed below. If the registry keys have commands assigned, the FodHelper will execute them in an elevated context without prompting the user. 

HKCU:\Software\Classes\ms-settings\shell\open\command

HKCU:\Software\Classes\ms-settings\shell\open\command\DelegateExecute

HKCU:\Software\Classes\ms-settings\shell\open\command\(default)

Windows Defender, by default, detects if there are attempts to write to the registry keysHKCU:\Software\Classes\ms-settings\shell\open\command and to evade this detection, the threat actor uses the programmatic identifier (ProgID). In Windows machines, a programmatic identifier (ProgID ) is a registry entry that can be associated with a Class ID (CLSID ), which is a globally unique serial number that identifies a COM (Component Object Model) class object. The Windows Shell uses a default ProgID registry key called CurVer, which is used to set the default version of a COM application. 

In this campaign, the threat actor abuses the “CurVer” registry key feature by creating a custom ProgID “ServiceHostXGRT” registry key in the software classes registry and assigns the Windows shell to execute a command to run the batch script. 

The script configures the ProgID ServiceHostXGRT in the CurVer registry subkey of HKCU\Software\Classes\ms-settings\CurVer, which will get translated to HKCU:\Software\Classes\ms-settings\shell\open\command. After modifying the registry settings, the PowerShell script runs FoDHelper.exe, executing the command assigned to the registry key HKCU:\Software\Classes\ms-settings\shell\open\command and executing the dropped batch script. Finally, it deletes the configured registry keys to evade detection. 

The batch script adds the folder “C:\ProgramData” to the Windows Defender exclusion list. The PowerShell loader script downloads the payload and saves it in the “C:\ProgramData” folder as “X1xDd.exe.”

After downloading the payload to the victim’s machine, the PowerShell loader executes another function that overwrites the previously dropped batch file with the new instructions to run the downloaded payload information stealer through the Windows start command. It again uses the same FoDHelper technique to run the batch script’s second version, which we explained earlier in this section.  

Actor’s choice of three payloads in the same campaign 

Talos discovered that the threat actor delivered three famous information stealer malware as payloads in this campaign, including CryptBot, LummaC2 and Rhadamanthys. These information stealers target victims’ information, such as system and browser data, credentials, cryptocurrency wallets and financial information. 

CryptBot

CryptBot is a typical infostealer targeting Windows systems discovered in the wild in 2019 by GDATA. It is designed to steal sensitive information from infected computers, such as credentials from browsers, cryptocurrency wallets, browser cookies and credit cards, and creates screenshots of the infected system. 

Talos has discovered a new CryptBot variant distributed in the wild since January 2024. The goal of the new CryptBot is the same, with some new innovative functionalities. The new CryptBot is packed with different techniques to obstruct malware analysis. A few new CryptBot variants are packed with VMProtect V2.0.3-2.13; others also have VMProtect, but with unknown versions. The new CryptBot attempts to steal sensitive information from infected machines and modifies the configuration changes of the stolen applications. The list of targeted browsers, applications and cryptocurrency wallets by the new variant of CryptBot is shown below.

We observed the new CryptBot variant also includes password manager application databases and authenticator application information in its stealing list to steal the cryptocurrency wallets that have two-factor authentication enabled. 

CryptBot is aware that the target applications in the victim’s environment will have different versions, and their database files will have different file extensions. It scans the victim’s machine for database files’ extensions of the targeted applications for harvesting credentials. 

LummaC2 

Talos discovered that the actor is delivering a new variant of LummaC2 malware as an alternative payload in this campaign. LummaC2 is a notorious information stealer that attempts to harvest information from victims’ machines. Based on the report posted by outpost24 and other external security reports, LummaC2 has already been confirmed to be sold on the underground market for years. 

The threat actor has modified LummaC2’s information stealer capability and obfuscated the malware with a custom algorithm. The obfuscation algorithm is saved in another section inside the malware shown below.

The new version of LummaC2 also presents the same signature of the alert message displayed to the user during its execution. 

The C2 domains are encrypted with a symmetric algorithm, and we found that the actor has nine C2 servers that the malware will attempt to connect to one by one. Analyzing various samples of the new LummaC2 variant, we spotted that each will use a different key to encrypt the C2.   

Talos has compiled the list of nine C2 domains the new LummaC2 variant attempts to connect in this campaign. 

LummaC2’s first step in its exfiltration phase is its connection to the C2 server. The malware will exit the process if it does not receive the “OK” message as a response from any of the nine C2 servers. The second step will be exfiltrating information from infected machines. The basic stealing functionality is the same as the previous version, with the addition of victims’ discord credentials to exfiltrate. 

Rhadamanthys

The last payload we found in this campaign is Rhadamanthys malware, a famous infostealer appearing in the underground forum advertisement in September 2022. The Rhadamanthys malware has been evolving till now, and its authors have released a new version, V0.6.0, on Feb. 15, 2024. However, the Rhadamanthys variant we found in this campaign is still v0.5.0.

The threat actor uses a Python executable file as a loader to execute the Rhadamanthys malware into memory. After decompiling the Python executable file, Python scripts load the Rhadamanthys malware in two stages. The first stage is a simple Python script that replaces the binary code from 0 to 9 and decodes the second stage. 

In the second stage, the Python script uses the Windows API to allocate a memory block and inject Rhadamanthys malware into the process. We spotted that the threat actor is developing the Python script with the intention of including the functionality of executing a shellcode. 

Analyzing the final executable file showed us that the malware unpacks the loader module with the custom format having the magic header “XS” and performs the process injection. The custom loader module in XS format is similar to that of a Rhadamanthys sample analyzed by the researcher at Check Point. The malware selects one of the listed processes as the target process for process injection from a hardcoded list in the binary:

• "%Systemroot%\\system32\\dialer.exe"
• "%Systemroot%\\system32\\openwith.exe"

Coverage

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks.

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here.

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat.

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products.

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here.

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center.

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SID for this threat is 63218 - 63225 and 300867 - 300870.

ClamAV detections are also available for this threat:

Lnk.Downloader.CoralRaider-10027128-0

Txt.Tool.CoralRaider-10027140-0

Html.Downloader.CoralRaider-10027220-0

Win.Infostealer.Lumma-10027222-0

Win.Infostealer.Rhadamanthys-10027293-0

Win.Infostealer.Rhadamanthys-10027294-0

Win.Infostealer.Cryptbot-10027295-0

Win.Infostealer.Cryptbot-10027296-0

Win.Infostealer.Cryptbot-10027297-0

Win.Infostealer.Cryptbot-10027298-0

Win.Infostealer.Cryptbot-10027299-0

Win.Infostealer.Cryptbot-10027300-0

Win.Infostealer.Cryptbot-10027301-0

Win.Infostealer.Cryptbot-10027302-0

Win.Infostealer.Cryptbot-10027303-0

Win.Infostealer.Cryptbot-10027305-0

Indicators of Compromise

Indicators of Compromise associated with this threat can be found here.

The National Vulnerability Database is usually the single source of truth for all things related to security vulnerabilities.  

But now, they’re facing an uphill battle against a massive backlog of vulnerabilities, some of which are still waiting to be analyzed, and others that still have an inaccurate or altogether missing severity score.  

As of April 9, 5,799 CVEs that have been published since Feb. 15, 2024, remain unanalyzed. 

As the backlog piles up, it’s unclear how, or when, the NVD is going to get back to its regular cadence of processing, scoring and analyzing vulnerabilities that are submitted to the U.S. government repository. At its current pace, the NVD is analyzing about 2.9 percent of all published CVEs it's been sent, well behind its pace in previous years. If there were no new CVEs submitted today, it could take the NVD more than 91 days to empty that backlog and get caught up. 

Given the state of the NVD and vulnerability management, we felt it was worth looking at the current state of the NVD, how we got to this point, what it means for security teams, and where we go from here. 

What is the NVD? 

The U.S.’s National Vulnerability Database provides the most comprehensive list of CVEs anywhere. This tracks security vulnerabilities in hardware and software and distributes that list to the public for anyone to use.  

This data enables organizations and large networks to automate vulnerability management, take appropriate security steps when a new vulnerability is discovered, important references and metrics that indicate how serious a particular vulnerability is.  

The U.S. National Institute of Standards and Technology (NIST) has managed the NVD since 2000, when it was started as the Internet Category of Attack toolkit. It eventually morphed into the NVD, which passed the 150,000-vulnerability mark in 2021.  

In addition to simply listing the CVEs that are regularly disclosed, the NVD scores vulnerabilities using the CVSS system, which often differ from the initial severity score that’s assigned by the researcher that discovers the vulnerability, or the company or organization behind the affected product or software. 

Since the creation of I-CAT, no other organization or private company has as comprehensive of a list of vulnerabilities as the NVD, nor do they offer it for free like NIST does.  

Why is the backlog a problem? 

On the surface, it may seem like the fact that the NVD has been slow to analyze CVEs isn’t all that bad, considering security issues are still being disclosed and patched every day (think: Microsoft Patch Tuesday). 

However, the lack of a single source of CVEs augmented information is detrimental to administrators, security researchers and users, and security experts are warning that the issue needs to be addressed quickly, or an alternative needs to be adopted.  

With the NVD being a collection of all this information, it’s up to the individual vendors to responsibly disclose and release vulnerabilities discovered in their products, which puts the onus on administrators to track that information down. If someone who handles patch management for a network was relying on the NVD for their information, that list is likely outdated at this point, and instead, they need to visit each individual vendor to find out what vulnerabilities were recently disclosed in their products, and how large of a risk they present.  

On any given network, that could be dozens to even hundreds of vendors, and while massive companies like Apple and Microsoft have easy-to-access security and vulnerability information, smaller open-source projects may not have the same resources that administrators need.  

The NVD is also the most trusted source for severity scores. Their calculations are generally what most users see when they read a security advisory. But without their input, it’s on the researcher or vendor to assign a score, instead. Under that system, there is no guarantee that a company may not want to score their vulnerability higher so it does not seem as serious, while researchers may want to bump up the severity of the issue they find so they are credited with discovering a higher-severity issue.  

As Talos has discussed before, a CVSS score is not the only metric worth relying on when patching, but it does play a major role in how the public views vulnerabilities and whether they’re likely to be exploited in the wild. According to Talos’ 2023 Year in Review report, eight of the 10 most-exploited CVEs last year received a severity score of 9.3 or higher. Any sense of uncertainty around CVSS scores can leave administrators scratching their heads and without a “north star” for patch management. 

The recent xz Utility vulnerability that was luckily prevented before any attackers could exploit it still does not have a Common Weakness Enumeration (CWE) assigned to it as of April 10 because of the backlog. Had an exploit for this been used, defenders would be missing crucial context and information for defending against this backdoor. 

How did this backlog develop? 

NIST has been relatively vague about why the agency has been slow to process new vulnerabilities. The first sign of trouble came in February, when NIST released a statement that a “growing backlog of vulnerabilities” had developed because of “an increase in software and, therefore, vulnerabilities, as well as a change in interagency support.” 

NIST’s budget was cut by about 12 percent after the recent package of funding bills passed by U.S. Congress, as well. 

The agency also said in February that additional NIST staff were being shifted around to address the backlog, and at the recent VulnCon and Annual CNA Summit, the NVD program director promised that NIST was developing a consortium to help address the issues with the NVD.  

The total number of vulnerabilities disclosed continues to increase every year, driven by larger amounts of software on the market and increased visibility into security concerns and research. Last year, there were 28,961 CVEs disclosed, according to the CVE Program, an increase of 15 percent from 2022. The last time there were fewer CVEs assigned in a year compared to the year prior was in 2016. 

What are some potential solutions? 

NIST has continued to publicly support the NVD and says it's preparing to revitalize the database. But it’s unclear what short- or long-term solutions or alternatives exist. 

Jerry Gamblin, a principal threat detection and response engineer for Cisco Vulnerability Management, said there has yet to be a company or organization willing to take on the monstrous task of tracking and scoring *every* CVE, especially for free.  

Other vulnerability catalogs exist like the Cybersecurity and Infrastructure Security Agency’s (CISA) Known Exploited Vulnerabilities (KEV) catalog, but the KEV only lists vulnerabilities that have actively been exploited in the wild. 

In short — all the potential alternatives are imperfect. 

“We can get the data from anywhere, and AI data could even help, but people just need to decide,” Gamblin said. “Is there going to be just one source of data? And who is the source of truth for this data? Who owns this data?” 

A private company like MITRE could step up to create its own solution, but it’d likely want to charge for access to that database. Any non-profit organization who also wants to step up would also likely need a massive influx of money and manpower to address the sheer volume of CVEs that come in every day. 

And while NIST says the consortium is in the works, there’s no timetable for how long it could take for that to be established, and which private companies would be involved.  

For now, it’s best to stick to tried-and-true patching strategies that have worked for years. Software, like Cisco Vulnerability Management, which has not been affected by the NVD backlog, can also assist in automating the patching process and prioritizing which vulnerabilities to patch first.  

If you’re a regular reader of this newsletter, you already know about how strongly I feel about the dangers of spreading fake news, disinformation and misinformation. 

And honestly, if you’re reading this newsletter, I probably shouldn’t have to tell you about that either. But one of the things that always frustrates me about this seemingly never-ending battle against disinformation on the internet, is that there aren’t any real consequences for the worst offenders. 

At most, someone who intentionally or repeatedly shares information on their social platform that’s misleading or downright false may have their account blocked, suspended or deleted, or just that one individual post might be removed.  

Twitter, which has become one of the worst offenders for spreading disinformation, has gotten even worse about this over the past few years and at this point doesn’t do anything to these accounts, and in fact, even promotes them in many ways and gives them a larger platform. 

Meta, for its part, is now hiding more political posts on its platforms in some countries, but at most, an account that shares fake news is only going to be restricted if enough people report it to Meta’s team and they choose to take action.  

Now, I’m hoping that Brazil’s Supreme Court may start imposing some real-world consequences on individuals and companies that support, endorse or sit idly by while disinformation spreads. Specifically, I’m talking about a newly launched investigation by the court into Twitter/X and its owner, Elon Musk.  

Brazil’s Supreme Court says users on the platform are part of a massive misinformation campaign against the court’s justices, sharing intentionally false or harmful information about them. Musk is also facing a related investigation into alleged obstruction.  

The court had previously asked Twitter to block certain far-right accounts that were spreading fake news on Twitter, seemingly one of the only true permanent bans on a social media platform targeting the worst misinformation offenders. Recently, Twitter has declined to block those accounts. 

This isn’t some new initiative, though. Brazil’s government has long looked for concrete ways to implement real-world punishments for spreading disinformation. In 2022, the Supreme Court signed an agreement with the equivalent of Brazil’s national election commission “to combat fake news involving the judiciary and to disseminate information about the 2022 general elections.” 

Brazil’s president (much like the U.S.) has been battling fake news and disinformation for years now, making any political conversation there incredibly divisive, and in many ways, physically dangerous. I’m certainly not an authority enough on the subject to comment on that and the ways in which the term “fake news” has been weaponized to literally challenge what is “fact” in our modern society.  

And I could certainly see a world in which a high court uses the term “fake news” to charge and prosecute people who are, in fact, spreading *correct* and verifiable information.  

But, even just forcing Musk or anyone at Twitter to answer questions about their blocking policies could bring an additional layer of transparency to this process. Suppose we want to really get people to stop sharing misleading information on social media. In that case, it needs to eventually come with real consequences, not just a simple block when they can launch a new account two seconds later using a different email address. 

The one big thing 

Talos recently discovered a new threat actor we're calling “Starry Addax” targeting mostly human rights activists associated with the Sahrawi Arab Democratic Republic (SADR) cause. Starry Addax primarily uses a new mobile malware that it infects users with via phishing attack, tricking their targets into installing malicious Android applications we’re calling “FlexStarling.” The malicious mobile application (APK), “FlexStarling,” analyzed by Talos recently masquerades as a variant of the Sahara Press Service (SPSRASD) App. 

Why do I care? 

The targets in this campaign's case are considered high-risk individuals, advocating for human rights in the Western Sahara. While that is a highly focused particular demographic, FlexStarling is still a highly capable implant that could be dangerous if used in other campaigns. Once infected, Starry Addax can use their malware to steal important login credentials, execute remote code or infect the device with other malware.  

So now what? 

This campaign's infection chain begins with a spear-phishing email sent to targets, consisting of individuals of interest to the attackers, especially human rights activists in Morocco and the Western Sahara region. If you are a user who feels you could be targeted by these emails, please pay close attention to any URLs or attachments used in emails with these themes and ensure you’re only visiting trusted sites. The timelines connected to various artifacts used in the attacks indicate that this campaign is just starting and may be in its nascent stages with more infrastructure and Starry Addax working on additional malware variants. 

Top security headlines of the week 

A threat actor with ties to Russia is suspected of infecting the network belonging to a rural water facility in Texas earlier this year. The hack in the small town of Muleshoe, Texas in January caused a water tower to overflow. The suspect attack coincided with network intrusions against networks belonging to two other nearby towns. While the attack did not disrupt drinking water in the town, it would mark an escalation in Russian APTs’ efforts to spy on and disrupt American critical infrastructure. Security researchers this week linked a Telegram channel that took credit for the activity with a group connected to Russia’s GRU military intelligence agency. The adversaries broke into a remote login system used in ICS, which allowed the actors to interact with the water tank. It overflowed for about 30 to 45 minutes before officials took the machine offline and switched to manual operations. According to reporting from CNN, a nearby town called Lockney detected “suspicious activity” on the town’s SCADA system. And in Hale Center, adversaries also tried to breach the town network’s firewall, which prompted them to disable remote access to its SCADA system. (CNN, Wired) 

Meanwhile, Russia’s Sandworm APT is also accused of being the primary threat actor carrying out Russia’s goals in Ukraine. New research indicates that the group is responsible for nearly all disruptive and destructive cyberattacks in Ukraine since Russia's invasion in February 2022. One attack involved Sandworm, aka APT44, disrupting a Ukrainian power facility during Russia’s winter offensive and a series of drone strikes targeting Ukraine’s energy grid. Recently, the group’s attacks have increasingly focused on espionage activity to gather information for Russia’s military to use to its advantage on the battlefield. The U.S. indicated several individuals for their roles with Sandworm in 2020, but the group has been active for more than 10 years. Researchers also unmasked a Telegram channel the group appears to be using, called “CyberArmyofRussia_Reborn.” They typically use the channel to post evidence from their sabotage activities. (Dark Reading, Recorded Future) 

Security experts and government officials are bracing for an uptick in offensive cyber attacks between Israel and Iran after Iran launched a barrage of drones and missiles at Israel. Both countries have dealt with increased tensions recently, eventually leading to the attack Saturday night. Israel’s leaders have already been considering various responses to the attack, among which could be cyber attacks targeting Iran in addition to any new kinetic warfare. Israel and Iran have long had a tense relationship that included covert operations and destructive cyberattacks. Experts say both countries have the ability to launch wiper malware, ransomware and cyber attacks against each other, some of which could interrupt critical infrastructure or military operations. The increased tensions have also opened the door to many threat actors taking claims for various cyber attacks or intrusions that didn’t happen. (Axios, Foreign Policy) 

Can’t get enough Talos? 

• Cisco Warns of Global Surge in Brute-Force Attacks Targeting VPN and SSH Services 
• Decade-old malware haunts Ukrainian police 
• Attackers are pummeling networks around the world with millions of login attempts 
• OfflRouter virus causes Ukrainian users to upload confidential documents to VirusTotal 
• Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials 
• Talos Takes Ep. #179: Why we need to stop calling as-a-service group takedowns "takedowns" 

Upcoming events where you can find Talos 

 Botconf (April 23 - 26) 

Nice, Côte d'Azur, France

This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants.

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Most prevalent malware files from Talos telemetry over the past week 

This section will be on a brief hiatus while we work through some technical difficulties. 

• During a threat-hunting exercise, Cisco Talos discovered documents with potentially confidential information originating from Ukraine. The documents contained malicious VBA code, indicating they may be used as lures to infect organizations. 
• The results of the investigation have shown that the presence of the malicious code is due to the activity of a rare multi-module virus that's delivered via the .NET interop functionality to infect Word documents. 
• The virus, named OfflRouter, has been active in Ukraine since 2015 and remains active on some Ukrainian organizations’ networks, based on over 100 original infected documents uploaded to VirusTotal from Ukraine and the documents’ upload dates. 
• We assess that OfflRouter is the work of an inventive but relatively inexperienced developer, based on the unusual choice of the infection mechanism, the apparent lack of testing and mistakes in the code. 
• The author’s design choices may have limited the spread of the virus to very few organizations while allowing it to remain active and undetected for a long period of time. 

As a part of a regular threat hunting exercise, Cisco Talos monitors files uploaded to open-source repositories for potential lures that may target government and military organizations. Lures are created from legitimate documents by adding content that will trigger malicious behavior and are often used by threat actors. 

For example, malicious document lures with externally referenced templates written in Ukrainian language are used by the Gamaredon group as an initial infection vector. Talos has previously discovered military theme lures in Ukrainian and Polish, mimicking the official PowerPoint and Excel files, to launch the so-called “Picasso loader,” which installs remote access trojans (RATs) onto victims' systems. 

In July 2023, threat actors attempted to use lures related to the NATO summit in Vilnius to install the Romcom remote access trojan. These are just some of the reasons why hunting for document lures is vital to any threat intelligence operation.  

In February 2024, Talos discovered several documents with content that seems to originate from Ukrainian local government organizations and the Ukrainian National Police uploaded to VirusTotal. The documents contained VBA code to drop and run an executable with the name `ctrlpanel.exe`, which raised our suspicion and prompted us to investigate further.   

Eventually, we discovered over 100 uploaded documents with potentially confidential information about government and police activities in Ukraine. The analysis of the code showed unexpected results – instead of lures used by advanced actors, the uploaded documents were infected with a multi-component VBA macro virus OfflRouter, created in 2015. The virus is still active in Ukraine and is causing potentially confidential documents to be uploaded to publicly accessible document repositories.   

Attribution 

Although the virus is active in Ukraine, there are no indications that it was created by an author from that region. Even the debugging database string used to name the virus “E:\Projects\OfflRouter2\OfflRouter2\obj\Release\ctrlpanel.pdb” present in the ctrlpanel.exe does not point to a non-English speaker. 

From the choice of the infection mechanism, VBA code generation, several mistakes in the code, and the apparent lack of testing, we estimate that the author is an inexperienced but inventive programmer.  

The choices made during the development limited the virus to a specific geographic location and allowed it to remain active for almost 10 years. 

OfflRouter has been confined to Ukraine 

According to earlier research by the Slovakian government CSIRT (Computer Security Incident Response Team) team, some infected documents were already publicly available on the Ukrainian National Police website in 2018.  

The newly discovered infected documents are written in Ukrainian, which may have contributed to the fact that the virus is rarely seen outside Ukraine. Since the malware has no capabilities to spread by email, it can only be spread by sharing documents and removable media, such as USB memory sticks with infected documents. The inability to spread by email and the initial documents in Ukrainian are additional likely reasons the virus stayed confined to Ukraine.  

The virus targets only documents with the filename extension .doc, the default extension for the OLE2 documents, and it will not try to infect other filename extensions. The default Word document filename extension for the more recent Word versions is .docx, so few documents will be infected as a result.  

This is a possible mistake by the author, although there is a small probability that the malware was specifically created to target a few organizations in Ukraine that still use the .doc extension, even if the documents are internally structured as Office Open XML documents.  

Other issues prevented the virus from spreading more successfully and most of them are found in the executable module, ctrlpanel.exe, dropped and executed by the VBA part of the code.  

When the virus is run, it attempts to set the value Ctrlpanel of the registry key HKLM\Software\Microsoft\Windows\CurrentVersion\Run so that it runs on the Windows boot. An internal global string _RootDir is used as the value, however, the string only contains the folder where the ctrlpanel.exe is found and not its full path, which makes this auto-start measure fail.  

One interesting concept in the .NET module is the entire process of infecting documents. As a part of the infection process, the VBA code is generated by combining the code taken from the hard-coded strings in the module with the encoded bytes of the ctrlpanel.exe binary. This makes the generated code the same for every infection cycle and rather easy to detect. Having a VBA code generator in the .NET code has more potential to make the infected documents more difficult to detect.  

Once launched, the executable module stays active in memory and uses threading timers to execute two background worker objects, the first one tasked with the infection of documents and the second one with checking for the existence of the potential plugin modules for the .NET module.  

The infection background worker enumerates the mounted drives and attempts to find documents to infect by using the Directory.Getfiles function with the string search pattern “*.doc” as a parameter.  

One of the parameters of the function is the SearchOption parameter which specifies the option to search in subdirectories or only the in the root folder. For fixed drives, the module chooses to search only the root folder, which is an unusual choice, as it is quite unlikely that the root folder will hold any documents to infect.  

For removable drives, the module also searches all subfolders, which likely makes it more successful. Finally, it checks the list of recent documents in Word and attempts to infect them, which contributes to the success of the virus spreading to other documents on fixed drives.  

OfflRouter VBA code drops and executes the main executable module 

The VBA part of the virus runs when a document is opened, provided macros are enabled, and it contains code to drop and run the executable module ctrlpanel.exe.

 The beginning of the macro code defines a function that checks if the file already exists and if it does not, it opens it for writing and calls functions CheckHashX, which at first glance looks like containing junk code to reset the value of the variable `Y`. However, the variable Y is defined as a private property with an overridden setter function, which converts the variable value assignment into appending the supplied value to the end of the opened executable module C:\Users\Public\ctrlpanel.exe. Every code line that looks like an assignment appends the assigned value to the end of the file, and that is how the executable module is written.  

This technique is likely implemented to make the detection of the embedded module a bit more difficult, as the executable mode is not stored as a contiguous block, but as a sequence of integer values that look like being assigned to a variable.  

To a more experienced analyst, this code looks like garbage code generated by polymorphic engines, and it raises the question of why the author has not extended the code generation to pseudo-randomize the code.  

The virus is unique, as it consists of VBA and executable modules with the infection logic contained in the PE executable .NET module.  

Ctrlpanel.exe .NET module 

The unique infection method used by ctrlpanel.exe is through the Office Interop classes of .NET VBProject interface Microsoft.Vbe.Interop and the Microsoft.Office.Interop.Word class that exposes the functionality of the Word application.  

The Interop.Word class is used to instantiate a Document class which allows access to the VBA macro code and the addition of the code to the target document file using the standard Word VBA functions.  

When the .NET module ctrlpanel.exe is launched, it attempts to open a mutex ctrlpanelapppppp to check if another module instance is already running on the system. If the mutex already exists, the process will terminate.  

Suppose no other module instances are running. In that case, ctrlpanel.exe creates the mutex named “ctrlpanelapppppp”, attempts to set the registry run key so the module runs on system startup, and finally initializes two timers to run associated background timer callbacks – VBAClass_Timer_Callback and PluginClass_TimerCallback, implemented to start the Run function of the classes VBAClass and PluginClass, respectively. 

The VBAClass_Timer_Callback will be called one second after the creation of VBAClass_Timer timer and the PluginClass_Timer_Callback three seconds after the creation of the PluginClass_Timer.  

The full functionality of the executable module is implemented by two classes, VBAClass and PluginClass, specifically within their respective functions Backgroundworker_DoWork. 

VBAClass is tasked with generating VBA code and infecting other Word documents 

 The background worker function runs in an infinite loop and contains two major parts, the first is tasked with the document infection and the second with finding the documents to infect, the logic we already described above.  

The infection iterates through a list of the document candidates to infect and uses an innovative method to check the document infection marker to avoid multiple infection processes – the function checks the document creation metadata, adds the creation times, and checks the value of the sum. If the sum is zero, the document is considered already infected.  

If the document to be infected is created in the Word 97-2003 binary format (OLE2), the document will be saved with the same name in Microsoft Office Open XML format with enabled macros (DOCX).  

The infection uses the traditional VBA class infection routine. It accesses the Visual Basic code module of the first VBComponent and then adds the code generated by the function MyScript to the document’s code module. After that, the infected document is saved.  

The code generation function MyScript contains static strings and instructions to dynamically generate code that will be added to infected documents. It opens its own executable ctrlpanel.exe for reading and reads the file 32-bit by 32-bit value which gets converted to decimal strings that can be saved as VBA code. For every repeating 32-bit value, most commonly for zero, the function creates a for loop to write the repeating value to the dropped file. The purpose is unclear, but it is likely to achieve a small saving in the size of the code and compress it.  

For every 4,096 bytes, the code generates a new CheckHashX subroutine to break the code into chunks. The purpose of this is not clear.  

 After the file is infected, the background worker adds the infection marker file by setting the values of hour, minute, second, and millisecond creation times to zero.

PluginClass is tasked with discovering and loading plugins 

Ctrlpanel.exe can also search for potential plugins present on removable media, which is very unusual for simple viruses that infect documents. This may indicate that the author’s aims were a bit more ambitious than the simple VBA infection. 

Searching for the plugins in removable drives is unusual as it requires the plugins to be delivered to the system on a physical media, such as a USB drive or a CD-ROM. The plugin loader searches for any files with the filename extension .orp, decodes its name using Base64 decoding function, decodes the file content using Base64 decoding, copies the file into the c:\users\public\tools folder with the previously decoded name and the extension .exe and finally executes the plugin. 

If the plugins are already present on an infected machine, ctrlpanel.exe will try to encode them using Base64 encoding, copy them to the root of the attached removable media with the filename extension “.orp” and set the newly created file attributes to the values system and hidden so that they are not displayed by default by Windows File Explorer. 

It is unclear if the initial vector is a document or the executable module ctrlpanel.exe 

The advantage of the two-module virus is that it can be spread as a standalone executable or as an infected document. It may even be advantageous to initially spread as an executable as the module can run standalone and set the registry keys to allow execution of the VBA code and changing of the default saved file formats to doc before infecting documents. That way, the infection may be a bit stealthier.  

The following registry keys are set: 
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Security\AccessVBOM (to allow access to Visual Basic Object Model by the external applications) 
  
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Security\VBAWarnings (to disable warnings about potential Macro code in the infected documents) 
  
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Options\DefaultFormat (to set the default format to DOC) 

Coverage 

Ways our customers can detect and block this threat are listed below. 

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.  

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here. 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Cisco Secure Network/Cloud Analytics (Stealthwatch/Stealthwatch Cloud) analyzes network traffic automatically and alerts users of potentially unwanted activity on every connected device.  

Cisco Secure Malware Analytics (formerly Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products. 

Umbrella, Cisco’s secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here. 

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.  

Additional protection with context to your specific environment and threat data are available from the Firewall Management Center.  

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.  

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SIDs for this threat are  

The following ClamAV signatures detect malware artifacts related to this threat: 

Doc.Malware.Valyria-6714124-0 

Win.Virus.OfflRouter-10025942-0 

IOCs 

IOCs for this research can also be found at our GitHub repository here. 

10e720fbcf797a2f40fbaa214b3402df14b7637404e5e91d7651bd13d28a69d8 - .NET module ctrlpanel.exe  

Infected documents  

2260989b5b723b0ccd1293e1ffcc7c0173c171963dfc03e9f6cd2649da8d0d2c 

2b0927de637d11d957610dd9a60d11d46eaa3f15770fb474067fb86d93a41912 

802342de0448d5c3b3aa6256e1650240ea53c77f8f762968c1abd8c967f9efd0 

016d90f337bd55dfcfbba8465a50e2261f0369cd448b4f020215f952a2a06bce 

Mutex 

ctrlpanelapppppp 

Cisco Talos would like to acknowledge Anna Bennett and Brandon White of Cisco Talos and Phillip Schafer, Mike Moran, and Becca Lynch of the Duo Security Research team for their research that led to the identification of these attacks.

Cisco Talos is actively monitoring a global increase in brute-force attacks against a variety of targets, including Virtual Private Network (VPN) services, web application authentication interfaces and SSH services since at least March 18, 2024.  

These attacks all appear to be originating from TOR exit nodes and a range of other anonymizing tunnels and proxies.  

Depending on the target environment, successful attacks of this type may lead to unauthorized network access, account lockouts, or denial-of-service conditions. The traffic related to these attacks has increased with time and is likely to continue to rise. Known affected services are listed below. However, additional services may be impacted by these attacks. 

• Cisco Secure Firewall VPN 
• Checkpoint VPN  
• Fortinet VPN  
• SonicWall VPN  
• RD Web Services 
• Miktrotik 
• Draytek 
• Ubiquiti 

The brute-forcing attempts use generic usernames and valid usernames for specific organizations. The targeting of these attacks appears to be indiscriminate and not directed at a particular region or industry. The source IP addresses for this traffic are commonly associated with proxy services, which include, but are not limited to:  

• TOR   
• VPN Gate  
• IPIDEA Proxy  
• BigMama Proxy  
• Space Proxies  
• Nexus Proxy  
• Proxy Rack 

The list provided above is non-exhaustive, as additional services may be utilized by threat actors.  

Due to the significant increase and high volume of traffic, we have added the known associated IP addresses to our blocklist. It is important to note that the source IP addresses for this traffic are likely to change.

Guidance 

As these attacks target a variety of VPN services, mitigations will vary depending on the affected service. For Cisco remote access VPN services, guidance and recommendation can be found in a recent Cisco support blog:  

Best Practices Against Password Spray Attacks Impacting Remote Access VPN Services 

IOCs 

We are including the usernames and passwords used in these attacks in the IOCs for awareness. IP addresses and credentials associated with these attacks can be found in our GitHub repository here. 

I feel like over the past several years, the “holiday” that is April Fool’s Day has really died down. At this point, there are few headlines you can write that would be more ridiculous than something you’d find on a news site any day of the week. 

And there are so many more serious issues that are developing, too, that making a joke about a fake news story is just in bad taste, even if it’s in “celebration” of a “holiday.” 

Thankfully in the security world, I think we’ve all gotten the hint at this point that we can’t just post whatever we want on April 1 of each calendar year and expect people to get the joke. I’ve put my guard down so much at this point that I actually did legitimately fall for one April Fool’s joke from Nintendo, because I could definitely see a world in which they release a Virtual Boy box for the Switch that would allow you to play virtual reality games. 

But at least from what I saw on April 1 of this year, no one tried to “get” anyone with an April Fool’s joke about a ransomware actor requesting payment in the form of “Fortnite” in-game currency, or an internet-connected household object that in no universe needs to be connected to the internet (which, as it turns out, smart pillows exist!).  

We’re already dealing with digitally manipulated photos of “Satanic McDonalds,” Twitter’s AI generating fake news about the solar eclipse, and an upcoming presidential election that is sure to generate a slew of misinformation, AI-generated photos and more that I hesitate to even make up. 

So, all that is to say, good on you, security community, for just letting go of April Fool’s. Our lives are too stressful without bogus headlines that we, ourselves, generate.  

The one big thing 

Talos discovered a new threat actor we’re calling “CoralRaider” that we believe is of Vietnamese origin and financially motivated. CoralRaider has been operating since at least 2023, targeting victims in several Asian and Southeast Asian countries. This group focuses on stealing victims’ credentials, financial data, and social media accounts, including business and advertisement accounts. CoralRaider appears to use RotBot, a customized variant of QuasarRAT, and XClient stealer as payloads. The actor uses the dead drop technique, abusing a legitimate service to host the C2 configuration file and uncommon living-off-the-land binaries (LoLBins), including Windows Forfiles.exe and FoDHelper.exe 

Why do I care? 

This is a brand new actor that we believe is acting out of Vietnam, traditionally not a country who is associated with high-profile state-sponsored actors. CoralRaider appears to be after targets’ social media logins, which can later be leveraged to spread scams, misinformation, or all sorts of malicious messages using the victimized account. 

So now what? 

CoralRaider primarily uses malicious LNK files to spread their malware, though we currently don’t know how those files are spread, exactly. Threat actors have started shifting toward using LNK files as an initial infection vector after Microsoft disabled macros by default — macros used to be a primary delivery system. For more on how the info in malicious LNK files can allow defenders to learn more about infection chains, read our previous research here. 

Top security headlines of the week 

The security community is still reflecting on the “What If” of the XZ backdoor that was discovered and patched before threat actors could exploit it. A single Microsoft developer, who works on a different open-source project, found the backdoor in xz Utils for Linux distributions several weeks ago seemingly on accident, and is now being hailed as a hero by security researchers and professionals. Little is known about the user who had been building the backdoor in the open-source utility for at least two years. Had it been exploited, the vulnerability would have allowed its creator to hijack a user’s SSH connection and secretly run their own code on that user’s machine. The incident is highlighting networking’s reliance on open-source projects, which are often provided little resource and usually only maintained as a hobby, for free, by individuals who have no connection to the end users. The original creator of xz Utils worked alone for many years, before they had to open the project because of outside stressors and other work. Government officials have also been alarmed by the near-miss, and are now considering new ways to protect open-source software. (New York Times, Reuters) 

AT&T now says that more than 51 million users were affected by a data breach that exposed their personal information on a hacking forum. The cable, internet and cell service provider has still not said how the information was stolen. The incident dates back to 2021, when threat actor ShinyHunters initially offered the data for sale for $1 million. However, that data leaked last month on a hacking forum belonging to an actor known as “MajorNelson.” AT&T’s notification to affected customers stated that, "The [exposed] information varied by individual and account, but may have included full name, email address, mailing address, phone number, social security number, date of birth, AT&T account number and AT&T passcode." The company has also started filing required formal notifications with U.S. state authorities and regulators. While AT&T initially denied that the data belonged to them, reporters and researchers soon found that the information were related to AT&T and DirecTV (a subsidiary of AT&T) accounts. (BleepingComputer, TechCrunch) 

Another ransomware group claims they’ve stolen data from United HealthCare, though there is little evidence yet to prove their claim. Change Health, a subsidiary of United, was recently hit with a massive data breach, pausing millions of dollars of payments to doctors and healthcare facilities to be paused for more than a month. Now, the ransomware gang RansomHub claims it has 4TB of data, requesting an extortion payment from United, or it says it will start selling the data to the highest bidder 12 days from Monday. RansomHub claims the stolen information contains the sensitive data of U.S. military personnel and patients, as well as medical records and financial information. Blackcat initially stated they had stolen the data, but the group quickly deleted the post from their leak site. A person representing RansomHub told Reuters that a disgruntled affiliate of Blackcat gave the data to RansomHub after a previous planned payment fell through. (DarkReading, Reuters) 

Can’t get enough Talos? 

• Talos Takes Ep. #178: Turla has been around for 20-plus years at this point, but they're still mixing things up 
• Vulnerability in some TP-Link routers could lead to factory reset 
• April’s Patch Tuesday includes 150 vulnerabilities, 60 which could lead to remote code execution 
• Vietnamese Cybercrime Group CoralRaider Nets Financial Data 
• Safeguarding Against CoralRaider: Protecting Your Data from Vietnamese Hackers 

Upcoming events where you can find Talos 

Botconf (April 23 - 26) 

Nice, Côte d'Azur, France

This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants.

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Most prevalent malware files from Talos telemetry over the past week 

SHA 256: c67b03c0a91eaefffd2f2c79b5c26a2648b8d3c19a22cadf35453455ff08ead0
MD5: 8c69830a50fb85d8a794fa46643493b2
Typical Filename: AAct.exe
Claimed Product: N/A
Detection Name: PUA.Win.Dropper.Generic::1201

SHA 256: abaa1b89dca9655410f61d64de25990972db95d28738fc93bb7a8a69b347a6a6
MD5: 22ae85259273bc4ea419584293eda886
Typical Filename: KMSAuto++ x64.exe
Claimed Product: KMSAuto++
Detection Name: W32.File.MalParent

SHA 256: 161937ed1502c491748d055287898dd37af96405aeff48c2500b834f6739e72d
MD5: fd743b55d530e0468805de0e83758fe9
Typical Filename: KMSAuto Net.exe
Claimed Product: KMSAuto Net
Detection Name: PUA.Win.Tool.Kmsauto::1201

SHA 256: b8aec57f7e9c193fcd9796cf22997605624b8b5f9bf5f0c6190e1090d426ee31
MD5: 2fb86be791b4bb4389e55df0fec04eb7
Typical Filename: KMSAuto Net.exe
Claimed Product: KMSAuto Net
Detection Name: W32.File.MalParent

SHA 256: 58d6fec4ba24c32d38c9a0c7c39df3cb0e91f500b323e841121d703c7b718681
MD5: f1fe671bcefd4630e5ed8b87c9283534
Typical Filename: KMSAuto Net.exe
Claimed Product: KMSAuto Net
Detection Name: PUA.Win.Tool.Hackkms::1201

Cisco Talos’ Vulnerability Research team has disclosed 10 vulnerabilities over the past three weeks, including four in a line of TP-Link routers, one of which could allow an attacker to reset the devices’ settings back to the factory default. 

A popular open-source software for internet-of-things (IoT) and industrial control systems (ICS) networks also contains multiple vulnerabilities that could be used to arbitrarily create new files on the affected systems or overwrite existing ones. 

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

Denial-of-service, remote code execution vulnerabilities in TP-Link AC1350 router 

Talos researchers recently discovered four vulnerabilities in the TP-Link AC1350 wireless router. The AC1350 is one of many routers TP-Link produces and is designed to be used on home networks. 

TALOS-2023-1861 (CVE-2023-49074) is a denial-of-service vulnerability in the TP-Link Device Debug Protocol (TDDP). An attacker could exploit this vulnerability by sending a series of unauthenticated packets to the router, potentially causing a denial of service and forcing the device to reset to its factory settings.  

However, the TDDP protocol is only denial of serviceavailable for roughly 15 minutes after a device reboot.  

The TDDP protocol is also vulnerable to TALOS-2023-1862 (CVE-2023-49134 and CVE-2023-49133), a command execution vulnerability that could allow an attacker to execute arbitrary code on the targeted device. 

There is another remote code execution vulnerability, TALOS-2023-1888 (CVE-2023-49912, CVE-2023-49909, CVE-2023-49907, CVE-2023-49908, CVE-2023-49910, CVE-2023-49906, CVE-2023-49913, CVE-2023-49911) that is triggered if an attacker sends an authenticated HTTP request to the targeted device. This exploit includes multiple CVEs because an attacker could overflow multiple buffers to cause this condition. 

TALOS-2023-1864 (CVE-2023-48724) also exists in the device’s web interface functionality. An adversary could exploit this vulnerability by sending an unauthenticated HTTP request to the targeted device, thus causing a denial of service. 

Multiple vulnerabilities in OAS Platform 

Discovered by Jared Rittle. 

Open Automation Software’s OAS Platform is an IoT gateway and protocol bus. It allows administrators to connect PLCs, devices, databases and custom apps. 

There are two vulnerabilities — TALOS-2024-1950 (CVE-2024-21870) and TALOS-2024-1951 (CVE-2024-22178) — that exist in the platform that can lead to arbitrary file creation or overwrite. An attacker can send a sequence of requests to trigger these vulnerabilities.  

An adversary could also send a series of requests to exploit TALOS-2024-1948 (CVE-2024-24976), but in this case, the vulnerability leads to a denial of service. 

An improper input validation vulnerability (TALOS-2024-1949/CVE-2024-27201) also exists in the OAS Engine User Configuration functionality that could lead to unexpected data in the configuration, including possible decoy usernames that contain characters not usually allowed by the software’s configuration. 

Arbitrary write vulnerabilities in AMD graphics driver 

Discovered by Piotr Bania. 

There are two out-of-bounds write vulnerabilities in the AMD Radeon user mode driver for DirectX 11. TALOS-2023-1847 and TALOS-2023-1848 could allow an attacker with access to a malformed shader to potentially achieve arbitrary code execution after causing an out-of-bounds write. 

AMD graphics drivers are software that allows graphics processing units (GPUs) to communicate with the operating system.  

These vulnerabilities could be triggered from guest machines running virtualization environments to perform guest-to-host escape. Theoretically, an adversary could also exploit these issues from a web browser. Talos has demonstrated with past, similar, vulnerabilities that they could be triggered from HYPER-V guest using the RemoteFX feature, leading to executing the vulnerable code on the HYPER-V host. 

In one of the largest Patch Tuesdays in years, Microsoft disclosed 150 vulnerabilities across its software and product portfolio this week, including more than 60 that could lead to remote code execution. 

Though April’s monthly security update from Microsoft is the largest since at least the start of 2023, only three of the issues disclosed are considered “critical,” all of which are remote code execution vulnerabilities in Microsoft Defender for IoT.  

Most of the remainder of the security issues are considered “important,” and only two are “moderate” severity. 

The three critical vulnerabilities — CVE-2024-21322, CVE-2024-21323 and CVE-2024-29053 — are all remote code execution vulnerabilities in Microsoft Defender for IoT. Though little information is provided on how these issues could be exploited, Microsoft did state that exploitation of these vulnerabilities is “less likely.”  

There are also three vulnerabilities Talos would like to highlight, as Microsoft as deemed them "more likely" to be exploited: 

• CVE-2024-26241: Elevation of privilege vulnerability in Win32k 
• CVE-2024-28903: Security feature bypass vulnerability in Windows Secure Boot 
• CVE-2024-28921: Security feature bypass vulnerability in Windows Secure Boot 

More than half of the code execution vulnerabilities exist in Microsoft SQL drivers. An attacker could exploit these vulnerabilities by tricking an authenticated user into connecting to an attacker-created SQL server via ODBC, which could result in the client receiving a malicious network packet. This could allow the adversary to execute code remotely on the client. 

A complete list of all the other vulnerabilities Microsoft disclosed this month is available on its update page. 

In response to these vulnerability disclosures, Talos is releasing a new Snort rule set that detects attempts to exploit some of them. Please note that additional rules may be released at a future date and current rules are subject to change pending additional information. Cisco Security Firewall customers should use the latest update to their ruleset by updating their SRU. Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. 

The rules included in this release that protect against the exploitation of many of these vulnerabilities are 63254 - 63257, 63265 - 63271, 63274 and 63275. There are also Snort 3 rules 300873, 300874 and 300877 - 300879.

• Cisco Talos is disclosing a new threat actor we deemed “Starry Addax” targeting mostly human rights activists associated with the Sahrawi Arab Democratic Republic (SADR) cause with a novel mobile malware. 
• Starry Addax conducts phishing attacks tricking their targets into installing malicious Android applications we’re calling “FlexStarling.” 
• For Windows-based targets, Starry Addax will serve credential-harvesting pages masquerading as login pages from popular media websites. 

Talos would like to thank the Yahoo! Paranoids Advanced Cyber Threats Team for their collaboration in this investigation. 

Starry Addax has a special interest in Western Sahara

The malicious mobile application (APK), “FlexStarling,” analyzed by Talos recently masquerades as a variant of the Sahara Press Service (SPSRASD) App. The Sahara Press Service is a media agency associated with the Sahrawi Arab Democratic Republic. The malware will serve content in the Spanish language from the SPSRASD website to look legitimate to the victim. However, in actuality, FlexStarling is a highly versatile malware capable of deploying additional malware components and stealing information from the infected devices. 

Starry Addax’s infrastructure can be used to target Windows- and Android-based users. This campaign's infection chain begins with a spear-phishing email sent to targets, consisting of individuals of interest to the attackers, especially human rights activists in Morocco and the Western Sahara region. The email contains content that requests the target to install the Sahrawi News Agency’s Mobile App or include a topical theme related to the Western Sahara.  

Some examples of the subject lines of the phishing emails consist of: 

The email originating from an attacker-owned domain, ondroid[.]site, consists of a shortened link to an attacker-controlled website and domain. Depending on the requestor’s operating system, the website will either serve the FlexStarling APK for Android devices or redirect the victim to a social media login page to harvest their credentials. The links observed by Talos so far are:  

Starry Addax likely to escalate momentum 

Campaigns like this that target high-value individuals usually intend to sit quietly on the device for an extended period. All components from the malware to the operating infrastructure seem to be bespoke/custom-made for this specific campaign indicating a heavy focus on stealth and conducting activities under the radar. The use of FlexStarling with a Firebase-based C2 instead of commodity malware or commercially available spyware indicates the threat actor is making a conscious effort to evade detections and operate without being detected. 

The timelines connected to various artifacts used in the attacks indicate that this campaign is just starting and may be in its nascent stages with more infrastructure and Starry Addax working on additional malware variants. 

FlexStarling – A highly capable implant 

The FlexStarling malware app requests a plethora of permissions from the Android OS to extract valuable information from the infected mobile device. The following list contains the permissions acquired by FlexStarling via its AndroidManifest[.]xml: 

Some of these permissions are dynamically requested at runtime: READ_CALL_LOG, READ_EXTERNAL_STORAGE, READ_SMS, READ_CONTACTS, WRITE_EXTERNAL_STORAGE, INTERNET, ACCESS_NETWORK_STATE, RECORD_AUDIO, READ_PHONE_STATE. 

Anti-emulation checks 

When the implant runs, it checks the BUILD information for keywords or phrases that indicate that it is running on an emulator or analysis tool. The implant checks for the following keywords: 

• BUILD[MANUFACTURER] does not contain: “Genymotion”. 
• BUILD[MODEL] does not contain any of: “google_sdk”, “droid4x”, “Emulator”, "Android SDK built for x86" 
• BUILD[HARDWARE] does not contains any of: “goldfish”, “vbox86”, “nox”. 
• BUILD[FingerPrint] does not start with “generic”. 
• BUILD[Product] does not consist of any of: “sdk”, “google_sdk”, “sdk_x86”, “vbox86p”, “nox”. 
• BUILD[Board] does not contain: “nox”. 
• BUILD[Brand] or Device does not start with “generic”.  

The implant also checks for the presence of the following emulation/virtualization-related files in the filesystem: 

• /dev/socket/genyd 
• /dev/socket/baseband_genyd 
• /dev/socket/qemud 
• /dev/qemu_pipe 
• ueventd.android_x86.rc 
• X86.prop 
• ueventd.ttVM_x86.rc 
• init.ttVM_x86.rc 
• fstab.ttVM_x86 
• fstab.vbox86 
• init.vbox86.rc 
• ueventd.vbox86.rc 
• fstab.andy 
• ueventd.andy.rc 
• fstab.nox 
• init.nox.rc 
• Ueventd.nox.rc 

If none of the keywords or files are found or all checks are passed, the malicious app tries to gain permissions for managing external storage areas (shared storage space) on the device using the permission “MANAGE_EXTERNAL_STORAGE”.  The actor wants to gain the ability to read, write, modify, delete and manage files on external storage locations.  

Stealing information and executing arbitrary code 

The malware obtains command codes and accompanying information from the C2 server. It then generates the MD5 hash string of the command code and compares its list of hardcoded hashes. The corresponding activity is carried out by the implant once a match is found. 

The various commands supported by the sample are: 

These commands are supported by accompanying information and consist of the following variables being sent across by the C2: 

DURL: Indicates the download URL used by the “Download” command above. 

APPNAME: Indicates the filename to use for the destination file during the “Download” command. 

DEX: Contains the source file name to be used during the Decrypt (and reflectively load) commands. 

ky1: Indicates a value to be used in the context of specific command codes: 

• Delete = File to be deleted. 
• Drop = File to be read and uploaded to Dropbox. 
• DECRYPT = Secret key used for AES decryption. 
• Check = Filename to be whose presence is to be checked in the application package directory. 

 ky2: Indicates a value to be used in the context of specific command codes: 

• Drop = Remote file location where the local file needs to be uploaded on Dropbox. 
• DECRYPT = IV used for AES decryption. 

 ky3: Indicates a value to be used in the context of specific command codes: 

• Drop = Dropbox ACCESS TOKEN value to be used during file upload. 
• DECRYPT = IV used for AES decryption. 

 fl: Filename used during the DEX reflective load process.  

ky4: Used as a parameter during reflective loading of the DEX file. 

ky5: Secret key used for AES decryption as part of the implant’s DEX decrypt and reflective load. 

ky6: IV used for AES decryption as part of the implant’s DEX decrypt and reflective load. 

ky7: Contains the source file name to be used during the AES decryption as part of the implant’s DEX decrypt and reflective load. 

Coverage 

Ways our customers can detect and block this threat are listed below. 

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here. 

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks. 

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here. 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products. 

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here. 

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them. 

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center. 

 Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network. 

 Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. 

IOCs 

IOCs for this research can also be found at our GitHub repository here. 

Hashes 

f7d9c4c7da6082f1498d41958b54d7aeffd0c674aab26db93309e88ca17c826c 

ec2f2944f29b19ffd7a1bb80ec3a98889ddf1c097130db6f30ad28c8bf9501b3 

Network IOCs 

hxxps[://]runningapplications-b7dae-default-rtdb[.]firebaseio[.]com 

ondroid[.]site 

ondroid[.]store 

bit[.]ly/48wdj1m 

www[.]ondroid[.]store/aL2mohh1 

bit[.]ly/48E4W3N 

www[.]ondroid[.]store/ties5shizooQu1ei/ 

As my manager knows, I’m not the biggest fan of working in a physical office. I’m a picky worker — I like my workspace to be borderline frigid, I hate dark mode on any software, and I want any and all lighting cranked all the way up.  

So, know that I’m biased going into this, but I also can’t get over the idea that companies are using cybersecurity as an excuse to create return-to-office policies in 2024.  

I started thinking about this because of the video game developer Rockstar, which owns some of the largest video game franchises on the planet like Red Dead Redemption and Grant Theft Auto. 

The company recently started asking its employees to return to its physical office five days a week in the name of productivity and security as the company pushes to finish its highly anticipated title “Grand Theft Auto VI.”  

Rockstar has long faced a number of cybersecurity concerns over the years, including a massive leak featuring early, in-progress gameplay of GTA VI in 2022 and other sensitive data. The attack was eventually attributed to the Lapsus$ group, and the perpetrator was eventually charged and sentenced. The first reveal trailer for the game was also leaked ahead of time.  

Many other companies have started to implement return-to-office policies over the past two years, citing various things ranging from worker productivity to interpersonal camaraderie, real estate costs, and more. I’m willing to hear arguments for all those things, but simply thinking that having employees all in one physical space is going to solve security problems seems far-fetched to me.  

We’ve written and talked about the various ways remote work has influenced cybersecurity since the onset of the COVID-19 pandemic. There’s no doubt that admins have had to implement new login methods, security controls and policies since more workers across the globe started working remotely. But four years into this trend, there’s no excuse to not be prepared to have remote workers anymore. 

An April 2023 study from Kent State University found that remote workers are more likely to be vigilant of security threats and take actions to ward them off than their in-office counterparts.  

The use of multi-factor authentication during the rise in remote work has skyrocketed, but often, this requirement is actually dropped if a user is physically in the office or accessing an on-site machine because of the perceived security of being in the office.  

The perceived security of a physical office can sometimes lull admins into a false sense of security, too, because machines located on-site may lack pre-boot authentication or encryption that’s commonly found on remote workers’ devices.  

I’m not saying that working in an office is inherently less secure than remote work, but I do believe that the risks are essentially the same. Regardless of where an employee is working from, they should be using app-based MFA to access all their services. Sensitive software and hardware should rely on passkeys or physical token access rather than outdated password policies that create easy-to-guess or shareable text-based passwords.  

And if security is the name of the game when asking employees to come back into the office, there’s still going to be a monetary investment that comes with that, too. 

Cisco’s recently published Global Hybrid Work study found that only 28 percent of responding employees say they would rank their employers’ office’s “Privacy and security features” as “very well.” To me, that says that even if employers want workers back in the office, they still need to upgrade their security, which is always going to mean more money and greater manpower.  

Security fundamentals should stay the same, no matter where your employees are. And suppose security is a chief concern for a company in wanting to go back to the “traditional” office lifestyle. In that case, I’m willing to bet they still have security gaps to overcome that simply can’t be solved by thinking they’ll be able to keep a closer eye on employees while they’re in the office to keep them from clicking on a phishing email. 

The one big thing 

Remote system management/desktop access tools such as AnyDesk and TeamViewer have grown in popularity since 2020. While there are many legitimate uses for this software, adversaries are also finding ways to use them for command and control in their campaigns. Cisco Talos Incident Response (Talos IR) has recently seen a spike in actors using this type of software as a method of gaining initial access to a network or to spy on the actions of users. Talos IR noted in its Quarterly Trends report for the third quarter of 2023, “AnyDesk was observed in all ransomware and pre-ransomware engagements [. . .], underscoring its role in ransomware affiliates' attack chains.” 

Why do I care? 

The use of these types of tools has increased since the start of the COVID-19 pandemic when remote work became more common. Since this software is legitimate, it can be easy for an attacker to compromise it and sit undetected on a network, bypassing traditional blocking methods. These tools introduce the ability for an adversary to potentially take full remote control of a system, are easy to download and install, and can be very difficult to detect since they are considered legitimate software. 

So now what? 

Adopting one, or at most two, approved remote management solutions will allow the organization to thoroughly test and deploy in the most secure possible configuration. Once a solution is approved and championed for the organization, other remote management/access tools should be explicitly banned by policy. Due to the complexity of implementing all these controls, detection rules can serve as a backup in case an adversary finds a way to circumvent these mitigations. 

Top security headlines of the week 

The U.S. and Britain have jointly filed chargers and sanctions against a Chinese state-sponsored actor known as APT31. The group is accused of a sweeping espionage campaign allegedly linked to China's Ministry of State Security (MSS) in the province of Hubei. The group reportedly targeted thousands of U.S. and foreign politicians, foreign policy experts and other high-profile targets. Individuals in the White House, U.S. State Department and spouses of officials were also among those targeted. The attacks aligned with geopolitical events affecting China, including economic tensions with the U.S., arguments over control of the South China Sea, and pro-democracy rallies in Hong Kong in 2019. A release from the U.S. Department of Justice stated that the campaigns involved more than 10,000 malicious emails, sent to targets in multiple continents, in what it called a “prolific global hacking operation.” The charges go on to say that APT31 hoped to compromise government institution networks and stealing trade secrets. Seven Chinese nationals are the target of the new sanctions for their alleged involvement with APT31, including the Wuhan XRZ corporation that is tied to the threat actor. (Reuters, U.S. Department of Justice) 

A silent backdoor on Linux machines was almost a massive supply chain attack, before a lone developer found malicious code hidden in software updates. The malicious code was hidden in two updates to xz Utils, an open-source data compression utility available on almost all installations of Linux and other Unix-like operating systems. Had it been successfully deployed, adversaries could have stashed malicious code in an SSH login certificate, upload it and execute it on the backdoored device. Whoever is behind this code likely spent years working on it, with open-source updates going back to 2021. The actor never actually took advantage of the malicious code, so it’s unclear what they planned to upload. Researchers eventually identified the vulnerability as CVE-2024-3094. The U.S. Cybersecurity and Infrastructure Security Agency warned government agencies to downgrade their xz Utils to older versions. (Ars Technica, Dark Reading) 

There is a massive backup with the National Vulnerabilities Database and, consequently, MITRE is unable to compile a list of all new vulnerabilities. A recent study from Flashpoint found that there was backlog of more than 100,000 vulnerabilities with no CVE number, and consequently, hadn’t been included in the NVD. Of those, 330 vulnerabilities had been exploited in the wild, yet defenders had not been made aware of them. The National Institute of Standards and Technology blamed the backup on an increase in the volume of software available to the public, leading to a larger number of vulnerabilities, as well as “a change in interagency support.” NIST has only analyzed about half of the more than 8,700 vulnerabilities that had been submitted so far in 2024. And in March alone, they only analyzed 199 out of the 3,370 vulnerabilities submitted. Several organizations have tried launching their own alternatives to the NVD, though adoption can still take a long time. NIST has also vowed to remain dedicated to the NVD and that it’s still regrouping its current efforts. (SecurityWeek, The Record by Recorded Future) 

Can’t get enough Talos? 

• Enterprise Imperatives: The Critical Importance of Threat Intelligence 
• Beware the gap between security readiness and confidence levels, Cisco warns 

Upcoming events where you can find Talos 

Botconf (April 23 - 26) 

Nice, Côte d'Azur, France

This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants.

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Most prevalent malware files from Talos telemetry over the past week 

SHA 256: a31f222fc283227f5e7988d1ad9c0aecd66d58bb7b4d8518ae23e110308dbf91  
MD5: 7bdbd180c081fa63ca94f9c22c457376 
Typical Filename: c0dwjdi6a.dll |
Claimed Product: N/A  
Detection Name: Trojan.GenericKD.33515991 

SHA 256: 744c5a6489370567fd8290f5ece7f2bff018f10d04ccf5b37b070e8ab99b3241
MD5: a5e26a50bf48f2426b15b38e5894b189
Typical Filename: a5e26a50bf48f2426b15b38e5894b189.vir
Claimed Product: N/A
Detection Name: Win.Dropper.Generic::1201

SHA 256: 3a2ea65faefdc64d83dd4c06ef617d6ac683f781c093008c8996277732d9bd66
MD5: 8b84d61bf3ffec822e2daf4a3665308c
Typical Filename: RemComSvc.exe
Claimed Product: N/A 
Detection Name: W32.3A2EA65FAE-95.SBX.TG

SHA 256: 0e2263d4f239a5c39960ffa6b6b688faa7fc3075e130fe0d4599d5b95ef20647 
MD5: bbcf7a68f4164a9f5f5cb2d9f30d9790 
Typical Filename: bbcf7a68f4164a9f5f5cb2d9f30d9790.vir 
Claimed Product: N/A 
Detection Name: Win.Dropper.Scar::1201 

SHA 256: 62dfe27768e6293eb9218ba22a3acb528df71e4cc4625b95726cd421b716f983
MD5: 0211073feb4ba88254f40a2e6611fcef
Typical Filename: UIHost64.exe
Claimed Product: McAfee WebAdvisor
Detection Name: Trojan.GenericKD.68726899

• Cisco Talos discovered a new threat actor we’re calling “CoralRaider” that we believe is of Vietnamese origin and financially motivated. CoralRaider has been operating since at least 2023, targeting victims in several Asian and Southeast Asian countries. 
• This group focuses on stealing victims’ credentials, financial data, and social media accounts, including business and advertisement accounts.
• They use RotBot, a customized variant of QuasarRAT, and XClient stealer as payloads in the campaign we analyzed.
• The actor uses the dead drop technique, abusing a legitimate service to host the C2 configuration file and uncommon living-off-the-land binaries (LoLBins), including Windows Forfiles.exe and FoDHelper.exe 

CoralRaider operators likely based in Vietnam 

Talos assesses with high confidence that the CoralRaider operators are based in Vietnam, based on the actor messages in their Telegram C2 bot channels and language preference in naming their bots, PDB strings, and other Vietnamese words hardcoded in their payload binaries. The actor’s IP address is located in Hanoi, Vietnam. 

 Our analysis revealed that the actor uses a Telegram bot, as a C2, to exfiltrate the victim’s data. This allowed us to collect information and uncover several invaluable indicators about the origin and activities of the attacker. 

The attacker used two Telegram bots: A “debug” bot for debugging, and an “online” bot where victim data was received. However, a Desktop image in the “debug” bot had a similar desktop and Telegram to the “online” bot. This showed that the actor possibly infected their own environment while testing the bot. 

Analyzing the images of the actor’s Desktop on the Telegram bot, we found a few Telegram groups in Vietnamese named “Kiém tien tử Facebook,” “Mua Bán Scan MINI,” and “Mua Bán Scan Meta.” Monitoring these groups revealed that they were underground markets where, among other activities, victim data was traded. 

In an image from the “debug bot,” we spotted the Windows device ID (HWID) and an IP address (118[.]71[.]64[.]18), located in Hanoi, Vietnam, that is likely to be CoralRaider’s IP address.

Talos’ research uncovered two other images that revealed a few folders on their OneDrive. One of the folders had a Vietnamese name, “Bot Export Chiến,” which is the same as one of the folders in the PDB strings of their loader component. Pivoting on the folder path in the PDB string, we discovered a few other PDB strings having similar paths but different Vietnamese names. We analyzed the discovered samples with the PDB strings and found they belong to the same loader family, RotBot. The Vietnamese name in the PDB string of the loader binary further strengthens our assessment that CoralRaider is of Vietnamese origin.

Another image we analyzed is an Excel spreadsheet that likely contained the victims’ data. We have redacted the images to maintain confidentiality. The spreadsheet has several tabs in Vietnamese, and their English translation showed us the tabs “Employee salary spreadsheet,” “advertising costs,” “website to buy copies,” “PayPal related,” and “can use.” The spreadsheet seemed to have multiple versions — the first was created on May 10, 2023. We also spotted that they have logged into their Microsoft Office 365 account with the display name “daloia krag” while accessing the spreadsheet, and CoralRaider likely operates the account. 

CoralRaider’s payload, XClient stealer analysis, showed us a few more indicators. CoralRaider had hardcoded Vietnamese words in several stealer functions of their payload XClient stealer. The stealer function maps the stolen victim’s information to hardcoded Vietnamese words and writes them to a text file on the victim machine’s temporary folder before exfiltration. One example function we observed is used to steal the victim’s Facebook Ads account that has hardcoded with Vietnamese words for Account rights, Threshold, Spent, Time Zone, and Date Created, etc.

The campaign  

Talos observed that CoralRaider is conducting a malicious campaign targeting victims in multiple countries in Asia and Southeast Asia, including India, China, South Korea, Bangladesh, Pakistan, Indonesia and Vietnam. 

The initial vector of the campaign is the Windows shortcut file. We are unclear on the technique the actor used to deliver the LNKs to the victims. Some of the shortcut file filenames that we observed during our analysis are:

• 자세한 비디오 및 이미지.lnk
• 設計內容+我的名片.lnk
• run-dwnl-restart.lnk
• index-write-upd.lnk
• finals.lnk
• manual.pdf.lnk
• LoanDocs.lnk
• DoctorReferral.lnk
• your-award.pdf.lnk
• Research.pdf.lnk
• start-of-proccess.lnk
• lan-onlineupd.lnk
• refcount.lnk

We also discovered a few notable unique drive serial numbers from the metadata of the Windows Shortcut files:

• A0B4-2B36
• FA4C-C31D
• 94AA-CEFB
• 46F7-AF3B

The attack begins when a user opens a malicious Windows shortcut file, which downloads and executes an HTML application file (HTA) from an attacker-controlled download server. The HTA file executes an embedded obfuscated Visual Basic script. The malicious Visual Basic script executes an embedded PowerShell script in the memory, which decrypts and sequentially executes three other PowerShell scripts that perform anti-VM and anti-analysis checks, bypass the User Access Controls, disables the Windows and application notifications on the victim’s machine, and finally downloads and run the RotBot. 

RotBot, the QuasarRAT client variant, in its initial execution phase, performs several detection evasion checks on the victim machine and conducts system reconnaissance. RotBot then connects to a host on a legitimate domain, likely controlled by the threat actor, and downloads the configuration file for the RotBot to connect to the C2. CoralRaider uses the Telegram bot as the C2 channel in this campaign. 

After connecting to the Telegram C2, RotBot loads the payload XClient stealer onto the victim memory from its resource and runs its plugin program. The XClient stealer plugin performs anti-VM and anti-virus software checks on the victim's machine. It executes its functions to collect the victim's browser data, including cookies, stored credentials, and financial information such as credit card details. It also collects the victim’s data from social media accounts, including Facebook, Instagram, TikTok business ads, and YouTube. It also collects the application data from the Telegram desktop and Discord application on the victim's machine. The stealer plugin can capture screenshots of the victim’s desktop and save them as a PNG file in the victim's machine’s temporary folder. With PNG files, the stealer plugin dumps the collected victim’s data from the browser and social media accounts in a text file and creates a ZIP archive. The PNG and ZIP files are exfiltrated to the attacker's Telegram bot C2.

RotBot loads and runs the payload  

RotBot, a remote access tool (RAT) compiled on Jan. 9, 2024, is downloaded and runs on the victim machine disguised as a Printer Subsystem application “spoolsv.exe.” RotBot is a variant of the QuasarRAT client that the threat actor has customized and compiled for this campaign. 

During its initial execution, RotBot performs several checks on the victim’s machine to evade detection, including IP address, ASN number, and running processes of the victim’s machine. It performs reconnaissance of system data on the victim machine. It also configures the internet proxy on the victim machine by modifying the registry key: 

Software\Microsoft\Windows\CurrentVersion\Internet 

Settings with the values:

ProxyServer = 127.0.0.1:80

ProxyEnable = 1

We observed that RotBot discovered in this campaign creates mutex in the victim machine as the infection markers​​ using the hardcoded strings in the binary.

RotBot loads and runs the XClient stealer module from its resources and uses the configuration parameters for its Telegram C2 bot from the downloaded configuration file. 

XClient stealer targets victims’ social media accounts. 

The XClient stealer sample we analyzed in this campaign is a .Net executable compiled on Jan. 7, 2024. It has extensive information-stealing capability through its plugin module and various modules for performing remote administrative tasks. 

XClient stealer has three primary functions that help it to avoid the radar. First, it will do virtual environment evasion if the victim’s machine runs in VMware or VirtualBox. It also checks if a DLL called sbieDll.dll exists in the victim machine file system to detect if it runs in the Sandboxie environment. XClient stealer also checks if anti-virus software, including AVG, Avast, and Kaspersky, is running on the victim’s machine. 

After bypassing all the checking functions, the XClient stealer captures the victim’s machine screenshot, saves it with the “.png” extension in the victim’s temporary user profile folder, and sends it to C2 through the URL “/sendPhoto.” 

XClient stealer steals victims’ social media web application credentials, browser data, and financial information such as credit card details. It targets Chrome, Microsoft Edge, Opera, Brave, CocCoc, and Firefox browser data files through the absolute paths of the respective browser installation paths. It extracts the contents of the browser database to a text file in the victim’s profile local temporary folder. 

XClient stealer hijacks and steals various Facebook data from the victim’s Facebook account. It sets custom HTTP header metadata along with the victim’s stolen Facebook cookie, and the username sends requests to Facebook APIs through the URLs below.

It checks if the victim’s Facebook is a business or ads account and uses regular expressions to search for access_token, assetID, and paymentAccountID. Using Facebook graph API, XClient attempts to collect an extensive list of information from the victim’s account, shown in the table below.

XClient stealer also collects the financial information from the victims’ Facebook business and ads accounts.

 Using the graph API, XClient stealer retrieves victims’ account friend list details and pictures. 

XClient stealer also targets the victim’s Instagram account and YouTube accounts through the URLs and collects various information, including username, badge_count, appID, accountSectionListRenderer, contents, title, data, actions, getMultiPageMenuAction, menu, multiPageMenuRenderer, sections and hasChannel. It collects the application data from the Telegram desktop and Discord application on the victim’s machine. XClient also collects the data from the victim’s TikTok business account and checks for business ads. 

Talos compiled the hardcoded HTTP request header metadata the XClient stealer uses in this campaign while retrieving the victim’s information from Facebook, Instagram, and YouTube accounts. 

Finally, the XClient stealer stores the victim’s social media data, which is collected into a text file in the local user profile temporary folder and creates a ZIP archive. The ZIP files were exfiltrated to the Telegram C2 through the URL “/sendDocument”.

Talos’ research of this campaign focused on discovering and disclosing a new threat actor of Vietnamese origin and their payloads. Additional technical details of the attack chain components of this campaign can be found in the report published by the researchers at QiAnXin Threat Intelligence Center. 

Coverage

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks.

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here.

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat.

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products.

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here.

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center.

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SID for this threat is 63192.

ClamAV detections are also available for this threat:

Lnk.Downloader.CoralRaider-10024620-0

Html.Downloader.CoralRaider-10025101-0

Win.Trojan.RotBot-10024631-0

Win.Infostealer.XClient-10025106-2

Indicators of Compromise

Indicators of Compromise associated with this threat can be found here.

• Remote system management/desktop access tools such as AnyDesk and TeamViewer have grown in popularity since 2020. While there are many legitimate uses for this software, adversaries are also finding ways to use them for command and control in their campaigns.
• There is no easy way to effectively block all unauthorized remote management tools, but security can be greatly improved through a combination of policy and technical controls.
• Early warning alerts can be configured to alert defenders to remote management software activity that may have circumvented the technical controls.

The remote management/access software problem

Since 2020, the use of remote system management/access tools such as AnyDesk and TeamViewer has exploded in popularity due to forced work-from-home during the COVID-19 pandemic.

Whether used by an IT help desk technician to fix a user’s remote system or by co-workers for collaboration, these tools play an essential role in most corporations’ digital functions. However, this convenience comes at a cost. These tools introduce the ability for an adversary to potentially take full remote control of a system, are easy to download and install, and can be very difficult to detect since they are considered legitimate software. 

Further complicating the task of recognizing the malicious use of these tools, many organizations struggle to combat “shadow IT” in which individual users or overly proactive IT personnel might install unauthorized remote management tools to accomplish a benign goal.

Cisco Talos Incident Response (Talos IR) is seeing adversaries capitalize on this opportunity in the wild. We recently noted in our Quarterly Trends report for the third quarter of 2023, “AnyDesk was observed in all ransomware and pre-ransomware engagements [. . .], underscoring its role in ransomware affiliates' attack chains.”

While AnyDesk is a legitimate application, it highlights the tremendous value that can be gained through a security program that intentionally focuses on preventing unauthorized use of these tools. Talos is referencing AnyDesk for the purposes of this blog post, but any remote management tool is at risk of these exploits. There are several policy changes, technical countermeasures and security alerts that admins and defenders can use to ensure that AnyDesk, and similar pieces of software, are only used for legitimate purposes when deployed.

Policy change suggestion: Pick one approved remote management tool

Adopting one, or at most two, approved remote management solutions will allow the organization to thoroughly test and deploy in the most secure possible configuration.

If possible, integration with other organizational technology such as Active Directory or multi-factor authentication (MFA) will provide additional layers of protection and verification. Tying the approved remote management solutions into these already structured security solutions can make it easier to build “early warning” detections and alerts around unauthorized connectivity and use.

Once a solution is approved and championed for the organization, other remote management/access tools should be explicitly banned by policy. Ideally, this should be accompanied by a software inventory audit and published guidance on approved/non-approved software for the organization. Training and consistent enforcement of this policy will help reduce the “shadow IT” noise in the environment and leave network defenders with more time to investigate true anomalies.

Technical controls

While very worthwhile, preventing unauthorized use of these tools is not simple. First, the scores of commercially available remote access tools make it difficult to address every option an adversary might use. Many of those tools are frequently updated, meaning that blocking the executables by their hash value is not as effective. 

Adversaries also commonly rename the executables, meaning that filename blocks aren’t going to be helpful, either. 

Many popular solutions operate over common ports and protocols, such as ports 80 and 443, making them difficult to block at the firewall, and remote access tool creators often decline to publish their central server IP addresses due to frequently changing resolutions, which limits the effectiveness of static IP address blocks. A combination of approaches and techniques is necessary to limit the opportunity for an adversary to use remote access/management tools in any given environment.

DNS security controls

One of the most effective methods for detecting, and sometimes blocking, the activities of unauthorized remote management/access software, is by auditing and blocking DNS queries associated with these tools.

If your organization uses Cisco Umbrella for DNS security, it’s fairly easy to review and block DNS queries related to unauthorized traffic.

To review what might already be on your network, log into the Umbrella console and view “Reporting > App Discovery > Unreviewed Apps,” filtered by the “Collaboration” and “IT Services Management” categories, this is an excellent starting point to identify unexpected remote access software.

Simply clicking “Block this app” gives the administrator the ability to block future DNS requests associated with any particular result. If you prefer to take an even more proactive approach, going to “Policies > Policy Components > Application Settings” allows you to search all applications currently categorized by Umbrella, whether they have been seen on your network or not, and block them by policy. Again, the “Collaboration” and “IT Services Management” categories should be the areas of focus for policy review.

As with all of these technical controls, there are a few limitations. The first major caveat is that this only works if the DNS queries are evaluated by your security stack. In the case of DNS traffic from a home user’s system not traveling over the corporate network, the activity would be invisible. The second major caveat is that some remote management software has direct peer-to-peer capabilities, meaning the software might not send a DNS query to an easily identifiable domain when initiating a connection. 

Firewall controls

While less scalable and reliable, basic IP address blocking can be beneficial for preventing unauthorized remote software connections. Some vendors list static IP addresses for their central servers on their support sites that can be leveraged to control this access. However, many vendor IP addresses change periodically, making the task a bit challenging.

Another potentially fruitful approach to firewall traffic blocking is by port number. For example, TeamViewer prefers to use port 5938, although it can fall back on the practically unblockable port 443. While blocking port 5938 would not stop the connection, a properly configured alert would provide defenders with an early warning that TeamViewer was trying to connect out.

Some firewalls also provide additional functionality around session content, similar to Umbrella’s capabilities. Firewalls such as Cisco’s Meraki provide an allow/block URL listing that can be configured to prevent connectivity to unapproved remote management software sites. Cisco Meraki can provide content filtering options that may be helpful in blocking remote management/access sites.

Administrators should consider that firewall controls to combat unauthorized remote software management connections can have unintended consequences and should be heavily tested and piloted prior to implementation.

Verify that IP addresses are dedicated to that application prior to blocking in order to avoid blocking Content Delivery Network (CDN) nodes or other cloud computing shared resources. 

Finally, network segmentation or micro-segmentation can be useful in blocking unauthorized remote management software usage. For instance, categorizing and organizing server resources separate from workstation resources can allow for more tailored options around blocking all unnecessary traffic at the firewall, include that which may be associated with remote management tools. Some organizations already do this well by integrating with group policy configurations.

Host-based controls

Windows Defender Application Control (WDAC) and AppLocker

Of all the controls discussed in this post, WDAC and AppLocker are the only ones that can offer almost 100 percent protection against unauthorized remote management/access software execution.

In their most secure configuration, which allows only pre-approved software to run, users or adversaries can't run unexpected executables. However, this comes at a cost, as the approved software baseline maintenance level of effort can be high, and the user experience can be very limited if they are not allowed to install applications as needed.

WDAC and AppLocker offer considerable flexibility in their policies, so some organizations choose to only lock down their critical servers, such as domain controllers, which leaves user system policies more flexible. This approach has benefits far beyond simply blocking remote access/management software, as it will stop most malware from executing, as well.

Keep in mind that, while WDAC is currently more difficult to configure, it has more advanced capabilities and Microsoft is positioning it as the replacement for AppLocker. At the moment, AppLocker is receiving security updates, but no new feature updates.

Registry filename blocks

It is possible to block remote management/access software execution by filename via a registry “DisallowRun” key. However, Talos IR does not recommend this approach, except as a containment measure during incident response, since it is not scalable as a preventative measure and is trivially easy to bypass by renaming the executable or modifying the registry. 

EDR blocks

Almost every modern EDR can block file hashes, which gives defenders the capability to block the hashes associated with remote management/access software installers and/or installed executables. However, similarly to the filename GPO blocks, this is not scalable or reliable as a proactive measure, since every new version of every software distribution will have a new hash value. This measure should be restricted to containment during incident response only. 

Some EDR solutions offer methods to block vulnerable or unauthorized software, albeit with significant caveats regarding the limitations of those capabilities. The authors of this article have not tested those capabilities but note them here for the sake of completeness.

Host-based firewalls

The recommendations for host-based firewall rules are much the same as standalone firewalls, covered above. These can be useful where administrators expect users to roam outside of the boundary of the corporate network, such as home workers off the corporate VPN or using a split-tunnel VPN implementation. 

Administrator permission restriction

Restricting administrator permissions so that most users cannot conduct administrator actions on their work computer, such as installing remote access/management software, can help limit an adversary’s ability to install this software after the initial compromise.

Applying the principle of least privilege, which includes both locking down local administrator permissions and limiting the permissions of users’ domain accounts, is considered standard best practice.

NAC controls

While network access control (NAC) solutions do not directly block the use of remote management software, they can ensure that all other technical controls are working properly before admitting an endpoint to the network. If the device is a rogue system or lacks EDR, for example, NAC would prevent it from joining.

Another benefit offered by a NAC solution is software version enforcement through custom rules. In Cisco ISE, for example, there are Posture Checks. Organizations can use this to ensure that only the approved version(s) of their approved remote management tool are allowed on the network, directly addressing the threat of an adversary introducing an older version of the approved solution to the network for malicious purposes.

Alerts and forensics

Due to the complexity of implementing all these controls, detection rules can serve as a backup in case an adversary finds a way to circumvent the previous mitigations we discussed. The possibilities for these “tripwire” detections are endless, and SOCs/threat-hunting teams should continuously think of ways to improve them, but some ideas are listed below.

Central log collection

The first prerequisite for any successful detections is to have centralized log aggregation. At the very minimum, this should ingest firewall logs, EDR alerts and Windows Event logs for key servers. 

SIEM alerts for suspicious strings

Setting up a simple alert that triggers upon observation of strings associated with unauthorized remote access/management software product names (e.g., “AnyDesk”) can be an effective way to proactively identify unexpected product installations that were not otherwise blocked.

For example, an MSI installation would generate an Event 11707 entry in the Windows Application Event logs containing the software product name. If the SIEM were ingesting and evaluating those event logs, it would fire an alert, thereby alerting the SOC to a potential installation. This rule would need to be tuned to avoid excessive false positives, but it could result in a valuable early detection method. 

SIEM alerts for firewall blocks on unique ports

Enhanced alerting may be necessary to draw a SOC’s attention to firewall blocks associated with remote management/access traffic. Firewalls continuously block traffic, generally dropping thousands or millions of packets per hour. With that in mind, SOCs are not alerted every time a firewall rule drops traffic — especially if the rule that drops the traffic is the Implicit Deny rule blocking all traffic that was not specifically allowed. However, if an internal host attempts to communicate over a port dedicated to remote access/management software, that might merit attention from the SOC. 

It's worth considering creating an SIEM rule that alerts on any firewall block event involving outbound traffic to certain key ports, for example, 5938 (associated with TeamViewer). That alert, while an indication that the network blocks are working as intended, would be a good indication that the SOC needs to investigate the system originating the traffic.

The level of effort required to properly secure remote management/access software is daunting. However, the frequency of use by adversaries makes that effort a necessity. In the wrong hands, these tools serve as a ready-made command and control mechanism. If an organization can afford to secure its VPN solution, it should almost certainly devote resources to locking down unauthorized remote management software, as well.

Welcome to this week’s threat source newsletter with Jon out, you’ve got me as your substitute teacher. 

I’m taking you back to those halcyon days of youth and that moment when you found out that you had a sub that day, will I be the teacher that just rolls in the TV cart and delivers the single greatest blast of freedom that you can have in a classroom, or will I be the teacher that strolls into your 4^th grade class and is appalled that you aren’t already conversant in Dostoevsky? Neither. Today I will be the old wizened oracle offering advice and attempting to answer one of the most asked questions I receive at public speaking engagements. So pull up a desk and don’t make that high pitched sound with a wet finger on the basket underneath the seat, because I know the old magicks.  

The number one question that I field after public speaking is “Why did they let you out of your cage to talk to normal people?” and honestly, I don’t really have an answer I just hope that no one notices. The next question is invariably a variation of “How did you become a threat hunter?”, “How do I get a job in cyber security?”, “How do I get a gig within Talos?” The answer is simply – be curious. Intellectual curiosity is the key. I’ll take it a step further when talking specifically about Talos and quote Walt Whitman (via Ted Lasso) and say, “Be curious, not judgmental” because being a positive part of the culture is as important as the deep arcane knowledge and skills that you need to get your foot in the door at Talos.  

There are a lot of paths that you can take in security and the various skill sets along each path vary but curiosity will carry you through each one. A lot of people will tell you to follow your passion and I will vehemently disagree; I will say to follow your aptitude. As you learn and grow within the field, you’ll find that some things come easily, don’t fight the wind in that scenario be the willow. If you are extremely early in your journey, find the helpers. There are tons of super helpful people, sites, and resources available to get you started and finding them is easy if you are curious. Attend a BSides or local security group like AHA. Install Snort and start learning what traffic looks like on the wire and create custom signatures. Install Kali and break things, in your own environment please. Combine the two and see where it will take you. If you are further along in your journey and are interested in taking the next step from analyst to malware research or reverse engineering, you can start with hasherezade's 1001 nights and see if you have the aptitude to follow that path. Don’t be afraid to try something and fail. Don’t expect to be good from the start. Don’t be afraid to ask questions and admit that you don’t know something – the most important things I’ve picked up usually come from “I don’t know, could you teach me?”.  

In the end there are truly almost as many paths as there are people doing the jobs. It’s crazy how varied the backgrounds on our teams are but curiosity is rampant.  

The one big thing 

The one big thing is that clearly, I’m substituting, and all is normal in the security world. Vulns continue to be exploited, security vendors continue to be consolidated, and everything is as it was in the world. THISISFINEDOTGIF.  

Why do I care? 

Because it’s what keeps us up at night. That and a warm cup of Liber-Tea.  

So now what? 

Now we deliver Managed Democracy on Hell Divers 2 – together.  

Top security headlines of the week 

A newly discovered vulnerability baked into Apple’s M-series of chips allows attackers to extract secret keys from Macs when they perform widely used cryptographic operations, academic researchers have revealed in a paper published Thursday. (Ars Technica, Wired    

Metasploit has announced the release of Metasploit Framework 6.4 which features several improvements and a new feature for Windows Meterpreter that allows for searching a process's memory for user-specified needles with support for regular expressions. (Rapid 7) 

Can’t get enough Talos? 

• Cisco Closes $28B Splunk Deal: 5 Big AI, Security And Partner Things To Know 
• Beers With Talos: The old people episode 
• Dissecting a complex vulnerability and achieving arbitrary code execution in Ichitaro Word 

Upcoming events where you can find Talos 

Botconf (April 23 - 26) 

Nice, Côte d'Azur, France

This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants.

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California 

Most prevalent malware files from Talos telemetry over the past week 

SHA 256: 7b3ec2365a64d9a9b2452c22e82e6d6ce2bb6dbc06c6720951c9570a5cd46fe5 
MD5: ff1b6bb151cf9f671c929a4cbdb64d86 
Typical Filename: endpoint.query 
Claimed Product: Endpoint-Collector 
Detection Name: W32.File.MalParent 

SHA 256: 9f1f11a708d393e0a4109ae189bc64f1f3e312653dcf317a2bd406f18ffcc507  
MD5: 2915b3f8b703eb744fc54c81f4a9c67f  
Typical Filename: VID001.exe  
Claimed Product: N/A  
Detection Name: Win.Worm.Coinminer::1201 

SHA 256: a31f222fc283227f5e7988d1ad9c0aecd66d58bb7b4d8518ae23e110308dbf91  
MD5: 7bdbd180c081fa63ca94f9c22c457376 
Typical Filename: c0dwjdi6a.dll 
Claimed Product: N/A  
Detection Name: Trojan.GenericKD.33515991 

SHA 256: 0e2263d4f239a5c39960ffa6b6b688faa7fc3075e130fe0d4599d5b95ef20647 
MD5: bbcf7a68f4164a9f5f5cb2d9f30d9790 
Typical Filename: bbcf7a68f4164a9f5f5cb2d9f30d9790.vir 
Claimed Product: N/A 
Detection Name: Win.Dropper.Scar::1201 

SHA 256: e38c53aedf49017c47725e4912fc7560e1c8ece2633c05057b22fd4a8ed28eb3 
MD5: c16df0bfc6fda86dbfa8948a566d32c1 
Typical Filename: CEPlus.docm 
Claimed Product: N/A  
Detection Name: Doc.Downloader.Pwshell::mash.sr.sbx.vioc 

Whether you want to call them “catfishing,” “pig butchering” or just good ‘old-fashioned “social engineering,” romance scams have been around forever.  

I was first introduced to them through the MTV show “Catfish,” but recently they seem to be making headlines as the term “pig butchering” enters the public lexicon. John Oliver recently covered it on “Last Week Tonight,” which means everyone my age with an HBO account heard about it a few weeks ago. And one of my favorite podcasts going, “Search Engine,” just covered it in an episode. 

The concept of “pig butchering” scams generally follows the same chain of events: 

• An unknown phone number texts or messages a target with a generally harmless message, usually asking for a random name disguised as an “Oops, wrong number!” text. 
• When the target responds, the actor tries to strike up a conversation with a friendly demeanor. 
• If the conversation persists, they usually evolve into “love bombing,” including compliments, friendly advice, ego-boosting, and saying flattering things about any photos the target has sent. 
• Sometimes, the relationship may turn romantic. 
• The scammer eventually “butchers” the “pig” that has been “fattened up” to that point, scamming them into handing over money, usually in the form of a phony cryptocurrency app, or just straight up asking for the target to send the scammer money somehow. 

There are a few twists and turns along the way based on the exact scammer, but that’s generally how it works. What I think is important to remember is that this specific method of separating users from their money is not actually new.  

The FBI seems to release a renewed warning about romance scams every Valentine’s Day when people are more likely to fall for a stranger online wanting to make a real connection and then eventually asking for money. I even found a podcast from the FBI in 2015 in which they warned that scammers “promise love, romance, to entice their victims online,” estimating that romance-related scams cost consumers $82 million in the last half of 2014.  

The main difference that I can tell between “pig butchering” and past romance scams is the sheer scale. Many actors running these operations are relying on human trafficking and sometimes literal imprisonment, forcing these people against their will to send these mass blocks of messages to a variety of targets indiscriminately. Oftentimes in these groups, scammers who are less “successful” in luring victims can be verbally and physically harassed and punished. That is, of course, a horrible human toll that these operations are taking, but they also extend far beyond the world of cybersecurity. 

In the case of pig butchering scams, it’s not really anything that can be solved by a cybersecurity solution or sold in a package. Instead, it relies on user education and the involvement of law enforcement agencies and international governments to ensure these farms can’t operate in the shows. The founders who run them are brought to justice. 

It’s never a bad thing that users become more educated on these scams, because of that, but I also feel it’s important to remember that romance-related scams, and really any social engineering built on a personal “relationship,” has been around for years, and “pig butchering” is not something new that just started popping up. 

These types of scams are ones that our culture has kind of just accepted as part of daily life at this point (who doesn’t get surprised when they get a call about their “car’s extended warranty?), and now the infrastructure to support these scams is taking a larger human toll than ever. 

The one big thing 

Talos has yet another round of research into the Turla APT, and now we’re able to see the entire kill chain this actor uses, including the tactics, techniques and procedures (TTPs) utilized to steal valuable information from their victims and propagate through their infected enterprises. Before deploying TinyTurla-NG, Turla will attempt to configure anti-virus software exclusions to evade detection of their backdoor. Once exclsions have been set up, TTNG is written to the disk, and persistence is established by creating a malicious service. 

Why do I care? 

Turla, and this recently discovered TinyTurlaNG tool that Talos has been writing about, is an international threat that’s been around for years, so it’s always important for the entire security community to know what they’re up to. Most recently, Turla used these tactics to target Polish non-governmental organizations (NGOs) and steal sensitive data.  

So now what? 

During Talos’ research into TinyTurla-NG, we’ve released several new rounds of detection content for Cisco Secure products. Read our past two blog posts on this actor for more.  

Top security headlines of the week 

The Biden administration issued a renewed warning to public water systems and operators this week, saying state-sponsored actors could carry out cyber attacks soon, citing ongoing threats from Iran and China. The White House and U.S. Environmental Protection Agency sent a letter to every U.S. governor this week warning them that cyber attacks could disrupt access to clean drinking water and “impose significant costs on affected communities.” The letter also points to the U.S. Cyber and Infrastructure Security Agency’s list of known exploited vulnerabilities catalog, asking the managers of public water systems to ensure their systems are patched against these vulnerabilities. The EPA pointed to Volt Typhoon, a recently discovered Chinese APT that has reportedly been hiding on critical infrastructure networks for an extended period. A meeting among federal government leaders from the EPA and other related agencies is scheduled for March 21 to discuss threats to public water systems and how they can strengthen their cybersecurity posture. (Bloomberg, The Verge) 

UnitedHealth says it's still recovering from a cyber attack that’s halted crucial payments to health care providers across the U.S., but has started releasing some of those funds this week, and expects its payment processing software to be back online soon. The cyber attack, first disclosed in February, targeted Change Healthcare, a subsidiary of United, that handles payment processing and pharmaceutical orders for hospital chains and doctors offices. UnitedHealth’s CEO said in a statement this week that the company has paid $2 billion to affected providers who spent nearly a month unable to obtain those funds or needing to switch to a paper billing system. A recently published survey from the American Hospital Association found that 94 percent of hospitals that responded experienced financial disruptions from the Change Healthcare attack, and costs at one point were hitting $1 million in revenue per day. (ABC News, CNBC) 

Nevada’s state court system is currently weighing a case that could undo end-to-end encryption across the U.S. The state’s Attorney General is currently suing Meta, the creators of Facebook, Instagram and WhatsApp, asking the company to remove end-to-end encryption for minors on the platform, with the promise of being able to catch and charge users who abuse the platform to lure minors. However, privacy advocates are concerned that any rulings against Meta and its encryption policies could have larger ripple effects, and embolden others to challenge encryption in other states. Nevada is arguing that Meta’s Messenger a “preferred method” for individuals targeting Nevada children for illicit activities. Privacy experts are in favor of end-to-end encryption because it safeguards messages during transmission and makes it more difficult for other parties to intercept and read them — including law enforcement agencies. (Tech Policy Press, Bloomberg Law) 

Can’t get enough Talos? 

• The LockBit story: Why the ransomware affiliate model can turn takedowns into disruptions 
• Cisco Closes $28B Splunk Deal: 5 Big AI, Security And Partner Things To Know 
• Talos Takes Ep. #176: Why no one should be relying on passive security in 2024 
• Dissecting a complex vulnerability and achieving arbitrary code execution in Ichitaro Word 
• Netgear wireless router open to code execution after buffer overflow vulnerability 

Upcoming events where you can find Talos 

Botconf (April 23 - 26) 

Nice, Côte d'Azur, France

This presentation from Chetan Raghuprasad details the Supershell C2 framework. Threat actors are using this framework massively and creating botnets with the Supershell implants.

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Most prevalent malware files from Talos telemetry over the past week 

SHA 256: 0e2263d4f239a5c39960ffa6b6b688faa7fc3075e130fe0d4599d5b95ef20647 
MD5: bbcf7a68f4164a9f5f5cb2d9f30d9790 
Typical Filename: bbcf7a68f4164a9f5f5cb2d9f30d9790.vir 
Claimed Product: N/A 
Detection Name: Win.Dropper.Scar::1201 

SHA 256: 9f1f11a708d393e0a4109ae189bc64f1f3e312653dcf317a2bd406f18ffcc507  
MD5: 2915b3f8b703eb744fc54c81f4a9c67f  
Typical Filename: VID001.exe  
Claimed Product: N/A  
Detection Name: Win.Worm.Coinminer::1201 

SHA 256: a31f222fc283227f5e7988d1ad9c0aecd66d58bb7b4d8518ae23e110308dbf91  
MD5: 7bdbd180c081fa63ca94f9c22c457376 
Typical Filename: c0dwjdi6a.dll |
Claimed Product: N/A  
Detection Name: Trojan.GenericKD.33515991 

SHA 256: 7b3ec2365a64d9a9b2452c22e82e6d6ce2bb6dbc06c6720951c9570a5cd46fe5 
MD5: ff1b6bb151cf9f671c929a4cbdb64d86 
Typical Filename: endpoint.query 
Claimed Product: Endpoint-Collector 
Detection Name: W32.File.MalParent 

SHA 256: e38c53aedf49017c47725e4912fc7560e1c8ece2633c05057b22fd4a8ed28eb3 
MD5: c16df0bfc6fda86dbfa8948a566d32c1 
Typical Filename: CEPlus.docm 
Claimed Product: N/A  
Detection Name: Doc.Downloader.Pwshell::mash.sr.sbx.vioc 

Cisco Talos is providing an update on its two recent reports on a new and ongoing campaign where Turla, a Russian espionage group, deployed their TinyTurla-NG (TTNG) implant. We now have new information on the entire kill chain this actor uses, including the tactics, techniques and procedures (TTPs) utilized to steal valuable information from their victims and propagate through their infected enterprises. 

• Talos’ analysis, in coordination with CERT.NGO, reveals that Turla infected multiple systems in the compromised network of a European non-governmental organization (NGO). 

• The attackers compromised the first system, established persistence and added exclusions to anti-virus products running on these endpoints as part of their preliminary post-compromise actions. 

• Turla then opened additional channels of communication via Chisel for data exfiltration and to pivot to additional accessible systems in the network.

Tracing Turla’s steps from compromise to exfiltration

Talos discovered that post-compromise activity carried out by Turla in this intrusion isn’t restricted to the sole deployment of their backdoors. Before deploying TinyTurla-NG, Turla will attempt to configure anti-virus software exclusions to evade detection of their backdoor. Once exclusions have been set up, TTNG is written to the disk, and persistence is established by creating a malicious service.

Preliminary post-compromise activity and TinyTurla-NG deployment

After gaining initial access, Turla first adds exclusions in the anti-virus software, such as Microsoft Defender, to locations they will use to host the implant on the compromised systems.

Turla then sets up the persistence of the TinyTurla-NG implants using one or more batch (BAT) files. The batch files create a service on the system to persist the TTNG DLL on the system. 

This technique is identical to that used by Turla in 2021 to achieve persistence for their TinyTurla implants. However, we’re still unsure why the actor uses two different batch files, but it seems to be an unnecessarily convoluted approach to evade detections.

In the case of TTNG, the service is created with the name “sdm” masquerading as a “System Device Manager” service. 

Batch file contents.

The creation and start of the malicious service kick starts the execution of the TinyTurla-NG implant via svchost[.]exe (Windows’ service container). TinyTurla-NG is instrumented further to conduct additional reconnaissance of directories of interest and then copy files to a temporary staging directory on the infected system, followed by subsequent exfiltration to the C2. TinyTurla-NG is also used to deploy a custom-built Chisel beacon from the open-sourced offensive framework.

Custom Chisel usage

On deployment, Chisel will set up a reverse proxy tunnel to an attacker-controlled box [T1573.002 - Encrypted Channel: Asymmetric Cryptography]. We’ve observed that the attackers leveraged the chisel connection to the initially compromised system, to pivot to other systems in the network. 

The presence of Windows Remote Management (WinRM)-based connections on the target systems indicates that chisel was likely used in conjunction with other tools, such as proxy chains and evil-winrm to establish remote sessions. WinRM is Microsoft’s implementation of the WS-Management protocol and allows Windows-based systems to exchange information and be administered using scripts or built-in utilities.

The overall infection chain is visualized below.

Turla tactics, tools and procedures flow.

Once the attackers have gained access to a new box, they will repeat their activities to create Microsoft Defender exclusions, drop the malware components, and create persistence, indicating that Turla follows a playbook that can be articulated as the following cyber kill chain.

Cyber kill chain.

Analyzing the traffic originating from Chisel revealed the tool beaconed back to its C2 server every hour.

While the infected systems were compromised as early as October 2023 and Chisel was deployed as late as December 2023, Turla operators conducted the majority of their data exfiltration using Chisel much later on Jan. 12, 2024 [T1041 - Exfiltration Over C2 Channel].

Coverage

Ways our customers can detect and block this threat are listed below.

Cisco Secure Endpoint (formerly AMP for Endpoints) is ideally suited to prevent the execution of the malware detailed in this post. Try Secure Endpoint for free here.

Cisco Secure Web Appliance web scanning prevents access to malicious websites and detects malware used in these attacks.

Cisco Secure Email (formerly Cisco Email Security) can block malicious emails sent by threat actors as part of their campaign. You can try Secure Email for free here.

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat.

Cisco Secure Malware Analytics (Threat Grid) identifies malicious binaries and builds protection into all Cisco Secure products.

Umbrella, Cisco's secure internet gateway (SIG), blocks users from connecting to malicious domains, IPs and URLs, whether users are on or off the corporate network. Sign up for a free trial of Umbrella here.

Cisco Secure Web Appliance (formerly Web Security Appliance) automatically blocks potentially dangerous sites and tests suspicious sites before users access them.

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center.

Cisco Duo provides multi-factor authentication for users to ensure only those authorized are accessing your network.

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org.

IOCS

Hashes

267071df79927abd1e57f57106924dd8a68e1c4ed74e7b69403cdcdf6e6a453b

d6ac21a409f35a80ba9ccfe58ae1ae32883e44ecc724e4ae8289e7465ab2cf40

ad4d196b3d85d982343f32d52bffc6ebfeec7bf30553fa441fd7c3ae495075fc

13c017cb706ef869c061078048e550dba1613c0f2e8f2e409d97a1c0d9949346

b376a3a6bae73840e70b2fa3df99d881def9250b42b6b8b0458d0445ddfbc044 

Domains

hanagram[.]jpthefinetreats[.]com

caduff-sa[.]chjeepcarlease[.]com

buy-new-car[.]com

carleasingguru[.]com

IP Addresses

91[.]193[.]18[.]120

Cisco Talos’ Vulnerability Research team recently disclosed three vulnerabilities across a range of products, including one that could lead to remote code execution in a popular Netgear wireless router designed for home networks. 

There is also a newly disclosed vulnerability in a graphics driver for some NVIDIA GPUs that could lead to a memory leak. 

All the vulnerabilities mentioned in this blog post have been patched by their respective vendors, all in adherence to Cisco’s third-party vulnerability disclosure policy. 

For Snort coverage that can detect the exploitation of these vulnerabilities, download the latest rule sets from Snort.org, and our latest Vulnerability Advisories are always posted on Talos Intelligence’s website.  

Netgear RAX30 JSON parsing stack-based buffer overflow vulnerability 

Discovered by Michael Gentile. 

The Netgear RAX30 wireless router contains a stack-based buffer overflow vulnerability that could allow an attacker to execute arbitrary code on the device.  

An adversary could send a targeted device a specially crafted HTTP request to eventually cause a buffer overflow condition. 

The RAX30 is a dual-band Wi-Fi router that’s commonly used on home networks. In an advisory about TALOS-2023-1887 (CVE-2023-48725), Netgear stated that the vulnerability “requires an attacker to have your WiFi password or an Ethernet connection to a device on your network to be exploited.” 

NVIDIA D3D10 driver out-of-bounds read vulnerability 

Discovered by Piotr Bania. 

TALOS-2023-1849 (CVE-2024-0071) is an out-of-bounds read vulnerability in the shader functionality of the NVIDIA D3D10 driver that runs on several NVIDIA graphics cards. Drivers like D3D10 are usually necessary for the GPU to function properly. 

An adversary could send a specially crafted executable or shader file to the targeted machine to trigger an out-of-bounds read and eventually leak memory.  

This vulnerability could be triggered from guest machines running virtual environments to perform a guest-to-host escape. Theoretically, it could be exploited from a web browser, but Talos tested this vulnerability from a Windows Hyper-V guest using the RemoteFX feature, leading to execution of the vulnerable code on the Hyper-V host. While RemoteFX is no longer actively maintained by Microsoft, some older machines may still use this software.  

An out-of-bounds read vulnerability exists in the Shader functionality of NVIDIA D3D10 Driver, Version 546.01, 31.0.15.4601. A specially crafted executable/shader file can lead to an out-of-bounds read. An attacker can provide a specially crafted shader file to trigger this vulnerability. 

An adversary could also use this vulnerability to leak host data to the guest machine. 

Denial-of-service vulnerability in Google Chrome Video Encoder 

Discovered by Piotr Bania. 

A denial-of-service vulnerability in Google Chrome’s video encoder could crash the browser.  

TALOS-2023-1870 is triggered if the targeted user visits an attacker-created website that contains specific code.  

Talos’ sample exploit runs a JavaScript code related to the Chrome video encoding functionality, eventually causing a denial-of-service in the browser and stopping all processes in Chrome.