2020 – SCRT Team Blog

State of Pentesting 2020

To many people, pentesting (or hacking in a broader sense) is a dark art mastered by some and poorly understood by most. It has evolved quite substantially throughout the years, guided by new vulnerabilities, changing behaviours and maybe most importantly the development and release of new tools, be they offensive or defensive.

Continuous Pentesting

At SCRT, we have been performing penetration tests for nearly 20 years now and have always tried to improve our methodologies to match client expectations and deliver the most accurate and useful results from each test we undertake.

Engineering antivirus evasion (Part II)

tl;dr To interact with the Windows operating system, software often import functions from Dynamic Link Libraries (DLL). These functions are listed in clear-text in a table called Import Address Table and antivirus software tend to capitalise on that to infer malicious behavioural detection. We show ideas and implementation of an obfuscator that allows to refactor any C/C++ software to remove this footprint, with a focus on Meterpreter. The source code is available at https://github.com/scrt/avcleaner.

Engineering antivirus evasion

tl;dr: this blog post documents some aspects of our research on antivirus software and how we managed to automatically refactor Meterpreter to bypass every AV/EDR we were put up against. While the ideas for every technique and the implementation of the string obfuscation pass are detailed below, we decided to publish details on API imports hiding / syscalls rewriting in future blog posts to keep this one as short as possible. The source code is available at https://github.com/scrt/avcleaner

SCRT on Covid-19 and Remote Access / Working From Home

Like everybody, SCRT has been adjusting to life under Covid-19 over the last weeks. Thankfully, we’ve been prepared for working from home for quite some time now as many of us do so during normal circumstances anyways. This is however not the case for all companies and we’ve unfortunately been called in to help some of them deal with the unwanted consequences of poorly setting up their remote access (read: they got hacked). So here is a quick blog post detailing the main issues we see with remote access systems and what can be done to avoid them.

Combining Request Smuggling and CBC Byte-flipping to stored-XSS

During a recent penetration test we stumbled upon a couple of issues which independently might not have warranted any attention, but when combined allowed to compromise other users by injecting arbitrary JavaScript into their browsers. It goes to show that even certain issues which might not always seem particularly interesting (such as self-XSS) can sometimes be exploited in meaningful ways. I’ll keep this mostly theoretical so as not to divulge any information on the actual targeted system.

SonicWall SRA and SMA vulnerabilities

Last year, Orange Tsai did some awesome research and discovered several vulnerabilities in SSL VPN providers which can allow an attacker to break into a network through the very device which is supposed to protect it. The vulnerable constructors were:

Palo Alto
Fortinet
Pulse Secure