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Before yesterdayShielder

QilingLab – Release

21 July 2021 at 15:00
Two years ago Ross Marks created the FridaLab challenge as a playground to test and learn how to use the Frida dynamic instrumentation toolkit. At that time, I solved FridaLab and wrote a writeup about it explaining the main APIs and usages of Frida for Android. This helped others to start getting familiar with it and as a reference when developing Frida scripts. After trying Qiling for some time I decided to follow Ross Marks’ steps and to develop a basic playground challenge to make use of the main Qiling features and I obviously called it QilingLab.

Hunting for bugs in Telegram's animated stickers remote attack surface

16 February 2021 at 08:00
Introduction At the end of October β€˜19 I was skimming the Telegram’s android app code, learning about the technologies in use and looking for potentially interesting features. Just a few months earlier, Telegram had introduced the animated stickers; after reading the blogpost I wondered how they worked under-the-hood and if they created a new image format for it, then forgot about it. Back to the skimming, I stumbled upon the rlottie folder and started googling.

Re-discovering a JWT Authentication Bypass in ServiceStack

2 November 2020 at 08:37
TL;DR ServiceStack before version 5.9.2 failed to properly verify JWT signatures, allowing to forge arbitrary tokens and bypass authentication/authorization mechanisms. The vulnerability was discovered and patched by the ServiceStack team without highlighting the actual impact, so we chose to publish this blog post along with an advisory. Routine checks –> Auth bypass During a Web Application Penetration Test for one of our customers, I noticed that after the login process through a 3rd-party Oauth service the web application used JWT tokens to track sessions and privileges.

Sometimes they come back: exfiltration through MySQL and CVE-2020-11579

28 July 2020 at 14:18
Let’s jump straight to the strange behavior: up until PHP 7.2.16 it was possible by default to exfiltrate local files via the MySQL LOCAL INFILE feature through the connection to a malicious MySQL server. Considering that the previous PHP versions are still the majority in use, these exploits will remain useful for quite some time. Like many other vulnerabilities, after reading about this quite-unknown attack technique (1, 2), I could not wait to find a vulnerable software where to practice such unusual dynamic.

1-click RCE on Keybase

27 April 2020 at 18:00
TL;DR Keybase clients allowed to send links in chats with arbitrary schemes and arbitrary display text. On Windows it was possible to send an apparently harmless link which, when clicked, could execute arbitrary commands on the victim’s system. Introduction Keybase is a chat, file sharing, git, * platform, similar to Slack, but with a security in-depth approach. *Everything* on Keybase is encrypted, allowing you to relax while syncing your private files on the cloud.

NotSoSmartConfig: broadcasting WiFi credentials Over-The-Air

20 April 2020 at 16:00
During one of our latest IoT Penetration Tests we tested a device based on the ESP32 SoC by EspressIF. While assessing the activation procedure we faced for the first time a beautiful yet dangerous protocol: SmartConfig. The idea behind the SmartConfig protocol is to allow an unconfigured IoT device to connect to a WiFi network without requiring a direct connection between the configurator and the device itself – I know, it’s scary.

Don’t open that XML: XXE to RCE in XML plugins for VS Code, Eclipse, Theia, …

24 October 2019 at 17:22
TL;DR LSP4XML, the library used to parse XML files in VSCode-XML, Eclipse’s wildwebdeveloper, theia-xml and more, was affected by an XXE (CVE-2019-18213) which lead to RCE (CVE-2019-18212) exploitable by just opening a malicious XML file. Introduction 2019 seems to be XXE’s year: during the latest Penetration Tests we successfully exploited a fair amount of XXEs, an example being https://www.shielder.it/blog/exploit-apache-solr-through-opencms/. It all started during a web application penetration test, while I was trying to exploit a blind XXE with zi0black.

Exploiting an old noVNC XSS (CVE-2017-18635) in OpenStack

19 October 2019 at 17:40
TL;DR:Β noVNC had a DOM-based XSS that allowed attackers to use a malicious VNC server to inject JavaScript code inside the web page. As OpenStack uses noVNC and its patching system doesn’t update third parties’ software, fully-updated OpenStack installations may still be vulnerable. Introduction Last week I was testing an OpenStack infrastructure during a Penetration Test. OpenStack is a free and open-source software platform for cloud computing, where you can manage and deploy virtual servers and other resources.

Exploiting Apache Solr through OpenCMS

13 April 2019 at 09:19
Tl;dr It’s possible to exploit a known Apache Solr vulnerability through OpenCMS. Introduction meme During one of my last Penetration Test I was asked to analyze some OpenCMS instances. Before the assessment I wasn’t really familiar with OpenCMS, so I spent some time on the official documentation in order to understand how it works, which is the default configuration and if there are some security-related configurations which I should check during the test.

Nagios XI 5.5.10: XSS to #

10 April 2019 at 13:10
Tl;dr A remote attacker could trick an authenticated victim (with β€œautodiscovery job” creation privileges) to visit a malicious URL and obtain a remote root shell via a reflected Cross-Site Scripting (XSS), an authenticated Remote Code Execution (RCE) and a Local Privilege Escalation (LPE). Introduction A few months ago I read about some Nagios XI vulnerabilities which got me interested in studying it a bit by myself. For those of you who don’t know what Nagios XI is I suggest you have a look at their website.

WebTech, identify technologies used on websites

8 March 2019 at 00:37
Introduction We’re very proud to release WebTech as open-source software. WebTech is a Python software that can identify web technologies by visiting a given website, parsing a single response file or replaying a request described in a text file. This way you can have reproducible results and minimize the requests you need to make to a target website. The RECON phase in a Penetration Test is one among the most important ones.

FridaLab – Writeup

4 February 2019 at 15:20
Today I solved FridaLab, a playground Android application for playing with Frida and testing your skills. The app is made of various challenges, with increasing difficulty, that will guide you through Frida’s potential. This is a writeup with solutions to the challenges in FridaLab. We suggest the reader to take a look at it and try to solve it by itself before reading further. In this writeup we will assume that the reader has a working environment with frida-server already installed on the Android device and frida-tools installed on the PC as well, since we will not cover those topics.

XSSGame by Google at #HITB2017AMS – Writeup

26 April 2017 at 10:19
CTF’s homepage During the last edition ofΒ HITBΒ in Amsterdam we partecipated in theΒ XSSGame by Google: 8Β XSS challenges to win a Nexus 5X. The various levels exposed common vulnerabilities present in modern web apps. Introduction Each level required to trigger the JavaScript’s alert functionΒ by creating an URL with a Cross-Site Scripting (XSS) payload inside, which should be executed without any user interaction: once it is executed, the server replies with the link to the following challenge.
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