Publications

Zone Identifier Alternate Data Stream information, commonly referred to as Mark-of-the-Web (abbreviated MOTW), can be a significant hurdle for red teamers and penetration testers, especially when attempting to gain an initial foothold.

Your payload in the format of an executable, MS Office file or CHM file is likely to receive extra scrutiny from the Windows OS and security products when that file is marked as downloaded from the internet. In this blog post we will explain how this mechanism works and we will explore offensive techniques that can help evade or get rid of MOTW.

Note that the techniques described in this blog post are not new. We have witnessed all of them being abused in the wild. Hence, this blog post serves to raise awareness on these techniques for both red teamers (for more realistic adversary simulations) and blue teamers (for better countermeasures and understanding of attacker techniques).

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In this blog post we are going to explore the power of well-known process monitoring utilities and demonstrate how the technology behind these tools can be used by Red Teams within offensive operations.

Having a good technical understanding of the systems we land on during an engagement is a key condition for deciding what is going to be the next step within an operation. Collecting and analysing data of running processes from compromised systems gives us a wealth of information and helps us to better understand how the IT landscape from a target organisation is setup. Moreover, periodically polling process data allows us to react on changes within the environment or provide triggers when an investigation is taking place.

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This is part 2 of a multipart blog series on RedELK: Outflank’s open sourced tooling that acts as a red team’s SIEM and also helps with overall improved oversight during red team operations.

In part 1 of this blog series I have discussed the core concepts of RedELK and why you should want something like this. In this blog post I will walk you through integrating RedELK into your red teaming infrastructure. In future parts I will explain the core functionality of RedELK, and on the alarming of detection by blue teams.

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This blog is about the SYLK file format, a file format from the 1980s that is still supported by the most recent MS Office versions. As it turns out, this file format is a very good candidate for creating weaponized documents that can be used by attackers to establish an initial foothold. In our presentation at DerbyCon 8 we already demonstrated some of the powers of SYLK.

In this blog post we will dive into additional details of this file format. We also provide recommendations for mitigations against weaponized SYLK files.

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In this blog post we will explain how you can enumerate Active Directory from Cobalt Strike using the Active Directory Service Interfaces (ADSI) in combination with C/C++. This may help staying under the radar in environments where PowerShell and .NET are heavily monitored.

Imagine you are in a TIBER, CBEST or other long-term red team assessment and finally managed to get a foothold into the target’s network. Many hours of preparation finally pay off and your payload plus C2 channel bypass the target’s security measures. How can you run your tools for the next steps in your attack (such as Active Directory reconnaissance), without triggering modern defenses on the compromised host such as AMSI or script block logging?

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In this blog post we will explore the use of direct system calls, restore hooked API calls and ultimately combine this with a shellcode injection technique called sRDI. We will combine these techniques in proof of concept code which can be used to create a LSASS memory dump using Cobalt Strike, while not touching disk and evading AV/EDR monitored user-mode API calls.

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At BlackHat Asia we released Evil Clippy, a tool which assists red teamers and security testers in creating malicious MS Office documents. Amongst others, Evil Clippy can hide VBA macros, stomp VBA code (via p-code) and confuse popular macro analysis tools. It runs on Linux, OSX and Windows.

In this blog post we will explore the features of Evil Clippy and the technology behind it. The latest source code of the tool can be found here:

https://github.com/outflanknl/EvilClippy

Latest binary releases are available at:

https://github.com/outflanknl/EvilClippy/releases

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This blog is a writeup of the various AMSI weaknesses presented at the Troopers talk ‘MS Office File Format Sorcery‘ and the Blackhat Asia presentation ‘Office in Wonderland’.

We will explore the boundaries and design weaknesses of AMSI for VBA that would allow attackers to bypass and evade this defensive mechanism. Note that attacks on the engine itself (such as in-memory patching) are out of scope for this post.

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In January and February 2019 Microsoft provided patches for CVE-2019-0540 and CVE-2019-0561, which were reported by Stan and me. We disclosed the details in our Blackhat Asia talk “Office in Wonderland”. Both vulnerabilities abuse a feature in word called “fields”. In this blog post we will dive into this.

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This multi-part blog post is about a tool we released: RedELK. In a few words you can describe it as a “Red Team’s SIEM”, although it actually does a few more things to ease the life of red teams. We released it right after our talk at BruCON 2018, and you may have already seen it at our GitHub. But until now we haven’t had the time to articulate our reasoning and give it a proper introduction.

This first part covers our reasoning. A the second part (soon to be released) we’ll dive into the technical details, explain basic usage and show you how you can benefit from using it as a red teamer.

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