metame is a simple metamorphic code engine for arbitrary executables.

From Wikipedia:

Metamorphic code is code that when run outputs a logically equivalent version of its own code under some interpretation. This is used by computer viruses to avoid the pattern recognition of anti-virus software.

metame implementation works this way:

1. Open a given binary and analyze the code
2. Randomly replace instructions with equivalences in logic and size
3. Copy and patch the original binary to generate a mutated variant

It currently supports the following architectures:

• x86 32 bits
• x86 64 bits

Also, it supports a variety of file formats, as radare2 is used for file parsing and code analysis.

Example of code before and after mutation:

Hint: Two instructions have been replaced in this snippet.

Here another example on how it can mutate a NOP sled into equivalent code:

pip install metame

This should also install the requirements.

You will also need radare2. Refer to the official website for installation instructions.

simplejson is also a "nice to have" for a small performance boost:

pip install simplejson

metame -i original.exe -o mutation.exe -d

Use metame -h for help.

This project is released under the terms of the MIT license.