metame is a simple metamorphic code engine for arbitrary executables.
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:
- Open a given binary and analyze the code
- Randomly replace instructions with equivalences in logic and size
- 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.
An 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:
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: