Awesome

X86 Shellcode Obfuscator

This is a WIP tool that performs shellcode obfuscation in x86 instruction set. If you want to learn more, check out my blog where I explain how it works:

X86 Shellcode Obfuscation - Part 1

X86 Shellcode Obfuscation - Part 2

X86 Shellcode Obfuscation - Part 3

Requirements

Tool requires distorm3 library, which you can easily install with pip:

pip install distorm3

Usage

usage: x86obf.py [-h] -i INPUT -o OUTPUT [-r RANGE] [-p PASSES] [-f MIXFLOW]

optional arguments:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        Input binary shellcode file
  -o OUTPUT, --output OUTPUT
                        Output obfuscated binary shellcode file
  -r RANGE, --range RANGE
                        Ranges where code instructions reside (e.g.
                        0-184,188-204)
  -p PASSES, --passes PASSES
                        How many passes should the obfuscation process go
                        through (def. 1)
  -f MIXFLOW, --mixflow MIXFLOW
                        Specify level of execution flow mixing (0-10) (def. 5)

Example 1:

python x86obf.py -i shellcode\test1.bin -o output.bin

Example 2:

python x86obf.py -i shellcode\exec_calc.bin -o output.bin -r 0-184
python x86obf.py -i shellcode\exec_calc.bin -o output.bin -r 0-184 -p 4
python x86obf.py -i shellcode\exec_calc.bin -o output.bin -r 0-184 -p 2 -f 10

Example 3:

python x86obf.py -i shellcode\msg_box.bin -o output.bin -r 0-196

If you want to run and test any obfuscated or not obfuscated shellcode, you can use the attached run_shell.py script:

python run_shell.py -i shellcode\exec_calc.bin