Perun's Fart

This is my own implementation of the Perun's Fart Evasion technique by Sektor7.

About the technique

• It creates a process in a suspende state
• Reads the ntdll.dll of the process and copied the syscall stubs of the Nt APIs to ntdll.dll in the memory of the current process
• Since, initially when a process is created, the loader is not initialized, so there is no hooks injected in the memory of the created process
• So, when the process is in suspended state, only the ntdll.dll is loaded in memory, and then the LdrpInitializeProcess function is called, which initializes the execution environment. (https://stackoverflow.com/questions/30026604/why-does-process-loads-modulesdlls-in-different-phases)
• Also, the created process is a child process of our current process. Therefore, we can take the address of the ntdll.dll of the current process, and use this same address to read from the memory of the remote suspended process

Changes I have tried to make

• Used Ldr structure to find the base address of ntdll.dll
• From the base address found the syscall stubs of all the Nt functions

References

1. https://blog.sektor7.net/#!res/2021/perunsfart.md
2. https://github.com/plackyhacker/Peruns-Fart
3. https://github.com/am0nsec/HellsGate/blob/master/HellsGate/main.c
4. https://github.com/paranoidninja/PIC-Get-Privileges/blob/main/addresshunter.h
5. https://www.ired.team/offensive-security/defense-evasion/retrieving-ntdll-syscall-stubs-at-run-time

Refer to my Blog post explaining this code : https://dosxuz.gitlab.io/post/perunsfart/