sheep-wolf – Exploit MD5 Collisions For Malware Detection


sheep-wolf is a tool to help you Exploit MD5 Collisions in software, specially malware samples which are commonly detected using MD5 hash signatures.

sheep-wolf - Exploit MD5 Collisions For Malware Detectionand then a malicious one (Wolf) that have the same MD5 hash. Please use this code to test if the security products in your reach use MD5 internally to fingerprint binaries and share your results by issuing a pull request updating the contents of results/!

Dependencies

  • 32-bit Windows (virtual) machine (64-bit breaks stuff)
  • Visual Studio 2012 to compile the projects (Express will do)
  • Fastcoll for collisions
  • Optional: Cygwin+MinGW to compile Evilize

How does it work?

  • shepherd.bat executes shepherd.exe with the user supplied command line arguments
    • shepher.exe generates a header file (sc.h) that contains the encrypted shellcode, the password and the CRC of the plain shellcode
  • shepherd.bat executes the build process of sheep.exe
    • sheep.exe is built with sc.hincluded by Visual Studio
  • shepherd.bat executes evilize.exe
    • evilize.exe calculates a special IV for the chunk of sheep.exe right before the block where the collision will happen
    • evilize.exe executes fastcoll.exe with the IV as a parameter
      • fastcoll.exe generates two 128 byte colliding blocks: a and b
    • evilize.exe replaces the original string buffers of sheep.exe so that they contain combinations a and b
    • The resulting files (evilize/wolf.exe and evilize/sheep.exe ) have the same MD5 hashes but behave differently. The real code to be executed only appears in the memory of evilize/wolf.exe.

You can download sheep-wolf here:

sheep-wolf-master.zip

Or read more here.

Posted in: Cryptography, Forensics, Malware

,


Latest Posts:


Arcane - Tool To Backdoor iOS Packages (iPhone ARM) Arcane – Tool To Backdoor iOS Packages (iPhone ARM)
Arcane is a simple script tool to backdoor iOS packages (iPhone ARM) and create the necessary resources for APT repositories.
SharpHose - Asynchronous Password Spraying Tool SharpHose – Asynchronous Password Spraying Tool
SharpHose is an asynchronous password spraying tool in C# for Windows environments that takes into consideration fine-grained password policies and can be run over Cobalt Strike's execute-assembly.
Axiom - Pen-Testing Server For Collecting Bug Bounties Axiom – Pen-Testing Server For Collecting Bug Bounties
Project Axiom is a set of utilities for managing a small dynamic infrastructure setup for bug bounty, basically a pen-testing server out of the box with 1-line.
Quasar RAT - Windows Remote Administration Tool Quasar RAT – Windows Remote Administration Tool
Quasar is a fast and light-weight Windows remote administration tool coded in C#. Used for user support through day-to-day administrative work to monitoring.
Pingcastle - Active Directory Security Assessment Tool Pingcastle – Active Directory Security Assessment Tool
PingCastle is a Active Directory Security Assessment Tool designed to quickly assess the Active Directory security level based on a risk and maturity framework.
Second Order - Subdomain Takeover Scanner Tool Second Order – Subdomain Takeover Scanner Tool
Second Order Subdomain Takeover Scanner Tool scans web apps for second-order subdomain takeover by crawling the application and collecting URLs (and other data)


Comments are closed.