Brute Ratel C4 Blogs

Keep yourself updated with the latest tactics and techniques using Brute Ratel C4.

  • Release v1.2 - Scandinavian Defense - Evading Every EDR On The Planet

    Release

    Brute Ratel v1.2 codename Scandinavian Defense is now available for download. The main highlight of this release is memory evasion and support for bringing in your own injection techniques via COFF. This release brings major improvements to the badger’s core, both staged and stageless thereby avoiding every EDR trap in memory. This release was tested against 17 different EDRs and Antiviruses prior to the release to detect and bypass all possible traps into memory. There are several major changes made to the sleep masking and dot net evasion techniques following the detection blog from MdSec on suspicious stack threads and dotnet execution detections. A quick summary of the changes can be found in the release notes. The below image shows some of the top tier EDRs which were tested against these techniques and evaded successfully in their highest prevention mode.

  • Release v1.1 - Stoffel's Escape

    Release

    Brute Ratel v1.1 codename Stoffel’s Escape is now available for download. This release brings several new feature additions and improvements to the Badger, Ratel Server and Commander, including a complete re-write of the badger’s core to avoid some subtle detection techniques following the Palo Alto blog. A quick summary of the changes can be found in the release notes. The release name (Stoffel’s Escape) gives subtle hints foreshadowing the nature of this release. This release could not have been better without the support from the blue team community. As BRc4 initially started as a personal project two years back, there were still some remnants of IOCs that needed to be changed. Palo Alto’s reversing blog came in as a surprise, but it only helped to rebuild the payload and optimize it in a certain way to avoid as many IOCs as possible. This release was focused to overcome all the IOCs listed in public or private blogs, conferences and github detections, till date, about Badger and change them to avoid attribution and detection.

  • Release v1.0 - Sicilian Defense

    Release

    Brute Ratel v1.0 codename Sicilian Defense is now available for download. This release brings several new feature additions and improvements to the Badger and Commander. The release is focused towards the Egress comms of the badger. There will be a follow up blog, post the release which will showcase the external C2 capabilities. A quick summary of the changes can be found in the release notes.

  • Release v0.9 - Checkmate

    Release

    Brute Ratel v0.9.0 (Checkmate) is biggest release for Brute Ratel till date. This release brings major changes to the Brute Ratel’s loader, reflective DLL, shellcode and the internal APIs being called. As detailed in the previous version, where several syscall injection techniques were added for evasion, but they were limited to the reflective DLL’s loader of BRc4 and the VEH (Vectored Exception Handler) API of Windows. This version uses an updated version of Syscalls for almost everything except a few of those which I was pretty sure would never be hooked since they are too noisy. This release was built after reverse engineering several top tier EDR and Antivirus DLLs. A quick summary of the changes can be found in the release notes.

  • Release v0.8 - Warfare Tactics

    Release

    Brute Ratel v0.8.0 (Warfare Tactics) is now available for download and provides a major update towards in-memory and network evasion features. This release bring plethora of new capabilities which provide a gateway for in-memory evasion features like self-debugging, unhooking syscalls and hooking your own payload for monitoring via Process Instrumentation. I have listed the technical details of the release below, however a detailed list on the features and bug fixes can be found in the release notes.

  • Release v0.7 - The Pain of Tsukuyomi

    Release

    Brute Ratel v0.7.0 (Tsukuyomi) is now available for download and provides a major update towards in-memory evasion and addition of open source tooling. This release also contains addition and conversion of several public BOFs to internal functions of Brute Ratel so that users won’t have to depend on public BOFs which might not necessarily be stable. This also helps to avoid VirtualAlloc API call for BOF allocation altogether which is an added cherry on the top. I have listed the technical details of the release below, however a detailed list on the features and bug fixes can be found in the release notes.

  • Release v0.6 - Resurrection

    Release

    Brute Ratel v0.6.0 (Resurrection) is now available for download and provides a major update towards the x86 architecture support and various in-memory execution features. This release contains a major rewrite of a portion of the backend which provides better stability, at the same time allowing to make feature additions easier for future releases. I have listed the technical details of the release below, however a detailed list on the features and bug fixes can be found in the release notes.

  • Release v0.5 - Syndicate

    Release

    Brute Ratel v0.5.0 (Syndicate) is now available for download and provides a major update towards several features and the user interface of Brute Ratel. Commander comes with a new user interface providing a much more granular information on the metadata of the C4 features which can be seen in the figure below.

  • PE Reflection: The King is Dead, Long Live the King

    Research Feature-update

    Reflective DLL injection remains one of the most used techniques for post-exploitation and to get your code executed during initial access. The initial release of reflective DLLs by Stephen Fewer provided a great base for a lot of offensive devs to build their tools which can be executed in memory. Later came in PowerShell and C# reflection which use CLR DLLs to execute managed byte code in memory. C# and PowerShell reflection are both subject to AMSI scan which perform string based detections on the byte code, which is not a lot different from your usual Yara rule detection. Reflective DLLs however provide a different gateway which at a lower level allows you to customize how the payload gets executed in memory. Most EDRs in the past 3-4 years have upgraded their capabilities to detect the default process injection techniques which utilize Stephen Fewer’s reflective loader along with his Remote Process Execution technique using the CreateRemoteThread API.

  • Update v0.4.2 - Chaos Theory

    Release

    This is a minor update to Brute Ratel C4 v0.4.1 (Chaos Theory) which was released a few days back. This update brings a minor feature release and a few UI bug fixes on Commander. The next major release will be focusing on Credential Harvesting. So, I decided to add the process mitigation policy feature as a minor update along with some bug fixes before I move to the next major release.