Passive Fingerprinting


Passive fingerprinting has been defined by Michal Zalewski’s tool p0f. Active Countermeasures had a need to integrate passive fingerprinting into Passer. For a tool to have consistent and meaningful output, a curated list of signatures is required. David Quartarolo was hired to create this functionality for Passer and he got a little carried away. This effort became SMUDGE.

SMUDGE taps into a curated repository of signatures maintained by Active Countermeasures, keeps the functionality of p0f, and will be continuously updated with additional features when needed.


Primary Features

  • Extremely fast identification of operating systems via passive fingerprinting.
  • Written in Python and available in PyPi.
  • Utilizes a curated repository of signatures.
  • Under active development.


Download Details

Smudge is available on Pypi:

Install with:
pip install smudge

Source code available on Github at:


Additional Resources


SMUDGE the new open-source passive fingerprinting tool

You may also be interested in:
Latest Active Countermeasures Blog Posts: