Smudge (actually break) a file so that it is detected as another type of file.

examples

smudging a file

This example takes a Mach-O executable, and writes the 8 magic bytes to make it look like a png. The 8 bytes that orinally were in the file is backed up to a test.bytes_backup file.

restoring a file

It is possible to restore the file using filesmudge too (assuming the .bytes_backup file is available)

install

pip install filesmudge
After installation, you should have the filesmudge commandline tool available to use.

usage & help

filesmudge accepts the --help parameter to get help.

~ » filesmudge --help
Usage: filesmudge [OPTIONS] COMMAND [ARGS]...

  Filesmudge. Smudge file magic bytes to look like other files.

Options:
  --help  Show this message and exit.

Commands:
  available   List available types for 'smudge'
  restore     Restore a smudged file from .bytes_backup
  smudge      Smudge magic bytes with a known type
  smudgeraw   Smudge magic bytes with raw bytes
  typedetect  Determine a file type based on magic bytes

All of the commands have their own help too and will explain the required parameters