Skip to content


Repository files navigation

Netzob : Protocol Reverse Engineering, Modeling and Fuzzing


See complete documentation here:

About Netzob

Netzob is an open source tool for reverse engineering, modelization, traffic generation and fuzzing of communication protocols.

Netzob is suitable for reversing network protocols, structured files and system and process flows (IPC and communication with drivers and devices). Netzob handles different types of protocols: text protocols (like HTTP and IRC), delimiter-based protocols, fixed fields protocols (like IP and TCP) and variable-length fields protocols (like TLV-based protocols).

Netzob can be used to infer the message format and the state machine of a protocol through passive and active processes. Its objective is to bring state of art academic researches to the operational field, by leveraging bio-informatic and grammatical inferring algorithms in a semi-automatic manner.

Once modeled or inferred, a protocol model can be used in our traffic generation engine, to allow simulation of realistic and controllable communication endpoints and flows.

Main features of Netzob

The main features of Netzob are:

Protocol Modelization

Netzob includes a complete model to represent the message format (aka its vocabulary) and the state machine of a protocol (aka its grammar).

Protocol Inference

The vocabulary and grammar inference component provides both passive and active reverse engineering of communication flows through automated and manuals mechanisms.

Traffic Generation

Given vocabulary and grammar models previously inferred or modelized, Netzob can understand and generate communication traffic with remote peers. It can thus act as either a client, a server or both.

Protocol Fuzzing

Netzob helps security evaluators by simplifying the creation of fuzzers for proprietary or undocumented protocols. Netzob considers the format message and state machine of the protocol to generate optimized and specific test cases. Both mutation and generation are available for fuzzing.

Import Communication Traces

Data import is available in two ways: either by leveraging the channel-specific captors (currently network and IPC --Inter-Process Communication), or by using specific importers (such as PCAP files, structured files and OSpy files).

Export Protocol Models

This module permits to export an model of a protocol in formats that are understandable by third party software or by a human. Current work focuses on export format compatible with main traffic dissectors (Wireshark and Scapy) and fuzzers (Peach and Sulley).

Netzob must be used as a Python 3 library. It can either be imported in your scripts or in your favorite interactive shell (ipython?).

More Information



Follow Netzob's official accounts (@Netzob)

Netzob has been initiated by security auditors of AMOSSYS and the CIDre research team of CentraleSupélec to address the reverse engineering and fuzzing of communication protocols.


The documentation is available online at:

If you want to build the documentation, run the following command:

$ sphinx-build -b html doc/documentation/source/ doc/documentation/build/

Get Started with Netzob

Install it

Installing Netzob system dependencies

First thing to do is to check the version of your python3 interpretor. Netzob requires at least Python 3.8:

$ python3 --version
Python 3.8.10

You have to install the following system dependencies:

$ apt-get install -y python3 python3-dev python3-setuptools virtualenv build-essential libpcap-dev libgraph-easy-perl libffi-dev

Then, create a virtualenv:

$ mkdir venv
$ virtualenv venv
$ source venv/bin/activate

Installing Netzob from PyPI

You can install Netzob from PyPI (recommended choice):

(venv) $ pip3 install netzob

Installing Netzob from sources

If you have retrieved Netzob sources, the installation procedure is:

(venv) $ pip3 install Cython==0.29.32  # Should be manually installed because of direct dependency
(venv) $ pip3 install -e .

API usage

Once installed, we recommend to use the Netzob API inside scripts, with the following statement to import Netzob:

from netzob.all import *

Start Netzob CLI

Netzob also provides its own CLI, in order to play interactively with it:

(venv) $ netzob


There are multiple ways to help-us.

Defects and Features Requests

Help-us by reporting bugs and requesting features using the Bug Tracker.

Join the Development Team

To participate in the development, you need to get the latest version, modify it and submit your changes.

You're interested in joining, please contact us!

Authors, Contributors and Sponsors

See the top distribution file AUTHORS.txt for the detailed and updated list of authors, contributors and sponsors.


This software is provided under the GPLv3 License. See the COPYING.txt file in the top distribution directory for the full license text.

The documentation is under the CC-BY-SA licence.


Zoby, the official mascot of Netzob.

Zoby, the official mascot of Netzob.