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✇NCC Group Research

Whitepaper – Practical Attacks on Machine Learning Systems

By: Jennifer Fernick

Written by Chris Anley, Chief Scientist, NCC Group

This paper collects a set of notes and research projects conducted by NCC Group on the topic of the security of Machine Learning (ML) systems. The objective is to provide some industry perspective to the academic community, while collating helpful references for security practitioners, to enable more effective security auditing and security-focused code review of ML systems. Details of specific practical attacks and common security problems are described. Some general background information on the broader subject of ML is also included, mostly for context, to ensure that explanations of attack scenarios are clear, and some notes on frameworks and development processes are provided.

This paper may be downloaded below:

✇Blog - Signal Labs

Rediscovering Epic Games 0-Days (Forever Unpatched?)

By: christopher vella

How It Started

So one day I was browsing ZDI (usually its the same sort of targets, lots of Foxit bugs, Adobe, Ivanti, etc) and noticed a couple entries by @izobashi (ZDI-22-537, ZDI-22-538) for Epic Games Launcher, there were two things that stood out:

  1. It wasn’t patched at time of advisory release (which means no patch in 120 days since reporting it, maybe unpatched forever?)

  2. It was file overwrite and file deletion bugs which can be leveraged for LPE, and affected the installer (these bugs are common and very familiar to me)

Now as a gamer (albeit not one with Epic’s launcher installed) I’ve had the displeasure of noting multiple vulnerabilities in gaming related software (alongside a strong dislike for anti-cheats in my kernel or acting as a hypervisor, though I understand why they do), I figured I’d check now if I can find these same bugs in the latest version of Epic’s launcher.

Although we don’t have a PoC or really any detailed information from the ZDI listings, the bugs are familiar enough that we can jump right in with our trusty ProcMon and see what we find.

Finding the bugs

After installing Epic’s launcher I immediately find the installer in C:\Windows\Installer (shh! its a secret directory), I know this is Epic’s MSI due to the signature matching Epic as expected:

The reason bugs in installers are common can be noted to a few factors:

  1. They typically auto-elevate to SYSTEM (even if you’re just a lowly non-administrative user)

  2. They can be executed in install / remove / repair modes that perform various operations, including file operations (copy, rename, delete) and can run arbitrary bundled scripts

  3. People don’t spend security $$$ on hardening their installers? (I don’t know, but it sure seems like it)

Before we go any further, lets configure our ProcMon, but first — why ProcMon?:

  1. Tells us what processes are doing (to an extent)

    1. What files they’re accessing

    2. What permissions they’re operating at

    3. What files / registry entries they’re reading / writing / deleting

  2. Is filterable

    1. Write rules to only show / capture what you’re interested in

Now to configure ProcMon, what are we looking for exactly?:

  1. File creation/opening events that satisfy the following:

    1. Operating on folders or files we can control

      1. Why? So we can redirect them via symlinks of course

        1. If it overwrites a file in C:\windows\system32, how would our lowly non-admin user control it?

        2. If it overwrites a file in C:\users\lowly_user\Desktop that we can control, its a different story!

        3. (Or any other location we have write or similar access to)

    2. ?? (There are more potentially interesting events, like paths or files that don’t exist that we may create, etc… but for this exercise we don’t care)

Now you may think if we exclude the following folders, that’d be good enough to meet our requirements above:

The point of the above is:

  • Capture CreateFile and Load Image operations

  • Ensure username contains NT (e.g. NT SYSTEM)

  • Exclude folders we can’t modify / control:

    • C:\ProgramData\Microsoft

    • C:\Program Files*

    • C:\Windows\

Can you think what the problem with the above excluded directories is?

..

….

Well actually there are multiple (for example, C:\windows\temp is typically user-writable! Meaning we actually can have some control over the contents of this directory, yet in the above filters we exclude it, although this isn’t an issue for this particular example).

The actual issue is excluding all of C:\Program Files, because Epic actually applies a permissive DACL on c:\Program Files (x86)\Epic Games\Launcher and its subfolders! (Not a great thing to do in general…)

This can be verified with icacls:

(Tip: Enumerate ACLs on everything -> install software -> enumerate again -> diff!)

Ok so lets ensure the path C:\Program Files (x86)\Epic Games\Launcher is included in our procmon filter and start capturing (In this case I’m going to remove the exclude for C:\Program Files and specifically include the launcher path above — once we have the trace we can play with the filters to see other interesting events too, like searching for operations that begin with Set to see renames, deletions, etc).

Lets right click the .msi file and press Repair, wait for it to complete and see if anything interesting happens.

Well that’s a lot.

To be honest its not surprising, the .msi in repair mode is there to, well, “repair” its files (which is typically achieved by replacing them with a pre-packaged good version).

Since the ACLs on this folder are weak, what would happen if we were to redirect one of these files elsewhere?

To test this, I’m going to show the two 0-days, first is the file overwrite.

Lets start by grabbing the symbolic testing tools from GPZ and compile them.

Now lets turn a folder (in this case, C:\Program Files (x86)\Epic Games\Launcher\Engine\Binaries\Win32 into a symlink pointing to \RPC Control:

(If you can’t delete Win32, try stopping Epic’s running processes first)

Ok now lets try the repair operation again and see what happens.

Ok so its looking for a DLL in our Win32 folder, however Win32 now points to \RPC Control and there doesn’t exist any \RPC Control\msvcp140_2.dll for the target to obtain a handle to.

Lets try creating this, and redirecting it to C:\Windows\System32\License.rtf as an example, now lets first note the size of our License.rtf file:

Ok so yours is likely not 7 bytes like mine, but note that mine only allows modification by Administrators or higher, users just have RX.

Now lets create the link to it:

Now press Retry on the msi error, and you’ll notice it continues and pops up another error (for a different DLL!)

However, note that License.rtf has been overwritten!

This is the first 0-day, arbitrary file overwrite!
To ensure this sticks, we can now delete Win32, recreate it as a regular folder (mkdir Win32) and press Retry, this should cause the installer to continue without any more errors and leave the file overwritten.
However, we can turn this into an arbitrary deletion vulnerability by causing the target to now delete License.rtf!

We can do this by simply pressing Cancel instead of retry! The target MSI will rollback its operations, and this will cause it to delete the overwritten file entirely!

With these two bugs (file overwrite + file deletion) we can actually leverage them for LPE, there’s other posts on achieving this (e.g. https://www.zerodayinitiative.com/blog/2022/3/16/abusing-arbitrary-file-deletes-to-escalate-privilege-and-other-great-tricks)

Whos taking bets how long these bugs will remain as 0-days in Epic’s launcher?

✇SentinelLabs

Targets of Interest | Russian Organizations Increasingly Under Attack By Chinese APTs

By: Tom Hegel

Executive Summary

  • SentinelLabs has identified a new cluster of threat activity targeting Russian organizations.
  • We assess with high-confidence that the threat actor responsible for the attacks is a Chinese state-sponsored cyber espionage group, as also recently noted by Ukraine CERT (CERT-UA).
  • The attacks use phishing emails to deliver Office documents to exploit targets in order to deliver their RAT of choice, most commonly Bisonal.
  • SentinelLabs has also identified associated activity targeting telecommunication organizations in Pakistan leveraging similar attack techniques.

Overview

On June 22nd 2022, CERT-UA publicly released Alert #4860, which contains a collection of documents built with the Royal Road malicious document builder, themed around Russian government interests. SentinelLabs has conducted further analysis of CERT-UA’s findings and has identified supplemental Chinese threat activity.

China’s recent intelligence objectives against Russia can be observed in multiple campaigns following the invasion of Ukraine, such as Scarab, Mustang Panda, ‘Space Pirates’, and now the findings here. ​​Our analysis indicates this is a separate Chinese campaign, but specific actor attribution is unclear at this time.

While the overlap of publicly reported actor names inevitably muddies the picture, it remains clear that the Chinese intelligence apparatus is targeting a wide range of Russian-linked organizations. Our findings currently offer only an incomplete picture of this threat cluster’s phishing activity, but they serve to provide perspective into an attacker’s ongoing operational objectives and a framework for our ongoing research.

Malicious Documents Targeting Russia

On June 22nd , Ukraine’s CERT-UA reported several RTF documents containing malicious code exploiting one or more vulnerabilities in MS Office. CERT-UA assessed that the documents, “Vnimaniyu.doc”, “17.06.2022_Protokol_MRG_Podgruppa_IB.doc”, and “remarks table 20.06.2022_obraza”, were likely built with the Royal Road builder and dropped the Bisonal backdoor. Royal Road is a malicious document builder used widely by Chinese APT groups, while Bisonal is a backdoor RAT unique to Chinese threat actors.

The CERT-UA advisory followed public reporting by our colleagues from nao_sec and Malwarebytes, who identified some of the first indicators and shared related samples and C2 servers. Building off this initial intelligence, SentinelLabs discovered a further related cluster of activity.

Timeline of Royal Road Malicious Documents

As we have observed over the years, Royal Road documents follow content themes relevant to their targets. Following that practice, it’s reasonable to assume that the targets in this recent cluster of activity are likely Russian government organizations.

One example of this cluster (f599ed4ecb6c61ef2f2692d1a083e3bb040f95e6) is a fake document mimicking a RU-CERT memo on increased phishing attacks.

Malicious document mimicking RU-CERT
Malicious document mimicking RU-CERT (Translated)

Another example is themed around telecommunication organizations (415ce2db3957294d73fa832ed844940735120bae).

Malicious Document – Russia Telecom Theme – “Пояснительная записка к ЗНИ.doc”
Malicious Document – Russia Telecom Theme – “Пояснительная записка к ЗНИ.doc” (Translated)

The example documents shown above both exploit CVE-2018-0798, a remote execution vulnerability in Microsoft Office to install the embedded malware.

Attribution to Chinese Threat Groups

The collection of files and infrastructure noted above could be considered related to the Tonto Team APT group (aka “CactusPete”, “Earth Akhlut”), a Chinese threat group that has been reported on for nearly ten years. However, we assess that link with only medium confidence due to the potential for shared attacker resources that could muddy attribution based on the currently available data. Known targets span the globe, with a particular interest in Northeast Asia, including governments, critical infrastructure, and other private businesses.

The attacker continues their long history of Russian targeting; however, the rate of Russian and Russia-relevant targets in recent weeks may indicate increased prioritization.

There are multiple connections of this activity to Chinese threat actors. As noted above, the documents are built with a commonly known malicious document builder used widely by Chinese APT groups, the shared toolkit often referred to as the “Royal Road” or the “8.t” builder.

These documents often contain metadata indicating the document creator’s operating system was using simplified Chinese, a trait we observed in our previous analysis of Scarab APT activity.

The malicious documents are generally used for the delivery of custom malware, such as the Bisonal RAT, which as noted by CERT-UA, is unique to Chinese groups, including Tonto Team. Bisonal has a uniquely long history of use and continued development by its creators, such as expanding features for file searching and exfiltration, anti-analysis and detection techniques, and maintaining generally unrestricted system control.

Additionally, the collection of C2 infrastructure associated with these various samples fall under a larger umbrella of known Chinese APT activity.

Related Activity of Interest

It’s also worth noting that there are still ongoing related attacks focused on non-Russian organizations, such as those against Pakistan.

For example, one file uploaded to VirusTotal (91ca78231bcacab0d5e6194041817b96252e65bf) from Pakistan is a May 2022 email message file to the Pakistan Telecommunication Authority, sent from a potentially compromised account in the Cabinet Division of the Pakistani government. This email contains the Royal Road attachment “Please help to Check.doc” (f444ff2386cd3ada204c3224463f4be310e5554a), dropping 85fac143c52e26c22562b0aaa80ffe649640bd29 and beaconing outbound to instructor.giize[.]com (198.13.56[.]122).

Phishing email containing malicious document

Conclusion

We assess with high confidence that the Royal Road-built malicious documents, delivered malware, and associated infrastructure are attributable to Chinese threat actors. Based on our observations, there’s been a continued effort to target Russian organizations by this cluster through well-known attack methods– the use of malicious documents exploiting n-day vulnerabilities with lures specifically relevant to Russian organizations. Overall, the objectives of these attacks appear espionage-related, but the broader context remains unavailable from our standpoint of external visibility.

Indicators of Compromise

IOC Description
f599ed4ecb6c61ef2f2692d1a083e3bb040f95e6 6/21/2022 Royal Road Document”Вниманию.doc”
cb8eb16d94fd9242baf90abd1ef1a5510edd2996 6/16/2022  Royal Road Document “Вниманию.doc”
41ebc0b36e3e3f16b0a0565f42b0286dd367a352 6/15/2022 (Estimate) Royal Road Document”Анкетирование Агентства по делам государственной службы.rtf”
2abf70f69a289cc99adb5351444a1bd23fd97384 6/20/2022 Royal Road Document”17.06.2022_Протокол_МРГ_Подгруппа_ИБ.doc”
supportteam.lingrevelat[.]com C2 Domain
upportteam.lingrevelat[.]com C2 Domain for cb8eb16d94fd9242baf90abd1ef1a5510edd2996
2b7975e6b1e9b72e9eb06989e5a8b1f6fd9ce027 6/21/2022 Royal Road Document”О_формировании_проекта_ПНС_2022_файл_отображен.doc”
a501fec38f4aca1a57393b6e39a52807a7f071a4 6/21/2022 Royal Road Document”замечания таблица 20.06.2022.doc”
415ce2db3957294d73fa832ed844940735120bae 6/23/2022 Royal Road Document”Пояснительная записка к ЗНИ.doc”
news.wooordhunts[.]com C2 Domain for 415ce2db3957294d73fa832ed844940735120bae
137.220.176[.]165 IP Resolved for C2 Domains news.wooordhunts[.]com supportteam.lingrevelat[.]com upportteam.lingrevelat[.]com
1c848911e6439c14ecc98f2903fc1aea63479a9f 6/23/2022 Royal Road Document”РЭН 2022.doc”
91ca78231bcacab0d5e6194041817b96252e65bf 5/12/2022 Phishing Email File
f444ff2386cd3ada204c3224463f4be310e5554a 5/12/2022 Royal Road Document”Please help to Check.doc”
instructor.giize[.]com C2 Server for f444ff2386cd3ada204c3224463f4be310e5554a

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