MODeflattener

Miasm's Ollvm Deflattener

MODeflattener deobfuscates control flow flattened functions obfuscated by OLLVM using Miasm.
https://mrt4ntr4.github.io/MODeflattener/

Flattened Flow	Deflattened Flow

Installation

git clone https://github.com/mrT4ntr4/MODeflattener.git
cd MODeflattener
pip3 install -r requirements.txt

Usage

└──╼ $python3 modeflattener.py -h
usage: modeflattener [-h] [-a] [-l LOG] filename patch_filename address

positional arguments:
  filename           file to deobfuscate
  patch_filename     deobfuscated file name
  address            obfuscated function address

optional arguments:
  -h, --help         show this help message and exit
  -a, --all          find functions recursively and deobfuscate if flattened
  -l LOG, --log LOG  logging level (default=INFO)

Supported Architectures

• x86

Bonus

• Tim Blazytko's flattening heuristic script
  While disassembling the specified function we can look out for other functions used by it and can make use of this script to automatically detect whether it is a flattened one and try to deobfuscate it. This has already been integrated into the tool!
• nop-hider idapython script
  This script hides the nop instructions from IDA graph view as the backbone is converted into a long nop chain after deobfuscation.

References

Dissecting LLVM Obfuscator - RPISEC
Automated Detection of Control-flow Flattening - Tim Blazytko