vxunderground/VX-API
FreeCollection of various WINAPI tricks / features used or abused by Malware
FreeFree tier
About vxunderground/VX-API
The VX-API is a collection of malicious functionality to aid in malware development. It includes various WINAPI features and abuses commonly used by malware, such as anti-debugging techniques, cryptography functions, error handling, evasion methods, and system fingerprinting. The repository is maintained by vx-underground and is designed to be explored using Visual Studio. It is recommended for security researchers, red teamers, and malware analysts. The code is modular, allowing users to copy, paste, and edit only the required components.
Key Features
Anti-debug functions (e.g., IsDebuggerPresentEx, CheckRemoteDebuggerPresent2, AdfCloseHandleOnInvalidAddress)
Cryptography functions (hashing, compression, pseudo-random generation, file integrity)
Error handling via Thread Environment Block (TEB) and NT status codes
Evasion techniques (AMSI bypass, sleep obfuscation, DLL unhooking, PE manipulation)
Fingerprinting (OS build number, locale, linked DLLs)
Modular design: usable as entire solution or individual snippets
Maintained by vx-underground with regular updates
Pros & Cons
Pros
- Comprehensive collection of real-world malware techniques
- Well-documented with function descriptions and original author credits
- Modular - can be stripped to only needed code
- Free and open source (permissive license)
- Actively maintained (version 2.01.015)
- Includes both classic and modern evasion methods
Cons
- Designed for malicious use - may have legal and ethical risks
- Requires Visual Studio and Windows environment
- Some functions depend on others, increasing complexity
- Not intended for production software without careful review
Best For
Malware development and researchRed team engagements and adversary simulationSecurity proof-of-concept creationUnderstanding Windows internals and security mechanismsEducational purposes for reverse engineering and exploit development
FAQ
What is the VX-API?
The VX-API is a collection of malicious functionality (WINAPI tricks and features) to aid in malware development, maintained by vx-underground.
Is the VX-API free to use?
Yes, it is open source and free. The README states you may use it in any manner you please.
What environment is required to use the VX-API?
It requires Visual Studio on Windows. The repository includes a .sln solution file for easy exploration.
Can I use only parts of the VX-API?
Yes, the repository encourages you to 'strip, copy, paste, delete, or edit this project's contents as much as you'd like.'