2023-09-05 13:06:34 +02:00
2023-12-04 20:14:05 +01:00
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2023-09-04 20:30:18 +02:00
2023-09-05 13:53:09 +02:00

patate-crypter

I am not responsible for any damage caused by this program. It was made as a learning experiment to gather more knowledge about anti virus.
The project structure is very messy because i wasn't planning on releasing it, sorry i guess.
I will not provide any support for running the program, it is only made for people interested in cyber security to learn more about how AV work.

Limitations

patate crypter officially supports 32bit DLLs and PEs. It might be possible to add x64 bit support without too much issues, but i never tried, maybe one day.
The crypter will link the library dynamically by default because statically linking the MSVC default librairies cuases the detections to go from 0/40 to 5/40 (see below).
There is an issue where the reallocations would fail for specific payloads, TOFIX.
There is code in the metadata.py file to generate random BMP images in the metadata of the PE but it makes the entropy go way to high (from 6.4 to 7.4) (see link).

Detection rate

There is currently 0/40 detections for a crypted meterperter :

How does it work ?

The crypter (compile time) works by :

  • storing the raw bytes of the payload into a buffer (XOR encrypted)
  • adding junk code/control flow flattening to the decryption stub
  • copying a Windows file signature on the generated PE (using SigThief)

Then the stub (at runtime) :

  • decrypts the sections of the payload one by one and encrypts them back after copying them into the memory (bypasses ESET AV emulation)
  • rebases the payload to its new base address
  • calls (Dll)main

How to run

python gui.py
Description
patate's crypter
Readme 237 KiB
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C++ 23.1%
C 0.8%