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Protocol Reverse Engineering, Modeling and Fuzzing

Project description

Continuous integration Code coverage Code health Doc Python3 IRC

About Netzob

Functional Description

Netzob is an opensource tool for reverse engineering, traffic generation and fuzzing of communication protocols. This tool allows to infer the message format (vocabulary) and the state machine (grammar) 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.

Netzob is suitable for reversing network protocols, structured files and system and process flows (IPC and communication with drivers and devices). Once inferred, a protocol model can be used in our traffic generation engine, to allow simulation of realistic and controllable communication endpoints and flows.

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).

Technical Description

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

Once installed, we recommend the following statement to import Netzob:

from netzob.all import *

Netzob’s source code is mostly made of Python (90%) with some specific extensions in C (6%).

More Information

Mailing list:Two lists are available, use the SYMPA web interface to register.
IRC:You can hang-out with us on Freenode’s IRC channel #netzob @
Wiki:Discuss strategy on Netzob’s wiki
Twitter:Follow Netzob’s official accounts (@Netzob)

Get Started with Netzob

Install it

First thing to do is to check the version of your python3 interpretor. Netzob requires python 3:

$ python3 --version
Python 3.4.2

As a ‘classic’ python project, Netzob is provided with its This file defines what and how to install the project on a python hosting OS.

This file depends on setuptools which like few other modules cannot be automatically installed. The reason why, you have to manually install the following bunch of prerequisites before initiating Netzob’s install process.

  • python3
  • python3-dev
  • python3-setuptools
  • build-essential

We also highly recommend to install the following additional dependencies:

  • python-sphinx (for the documentation)

Once the required dependencies are installed, you can build and install Netzob:

# python3 install

Or if you prefer a more developer-friendly install:

$ python3 develop --user

Docker container

A docker build is offered from the docker registry repository. You can download it from command line with the following command:

$ docker pull netzob/netzob

Start it

Once installed, running Netzob is as simple as executing the provided script:

$ ./netzob

This script is in Python’s path if you’ve installed Netzob, otherwise (in developer mode), it’s located in the top distribution directory.

Docker container

If you used the docker container, the following command will allow you to start netzob with your current directory attached to /data into the container:

$ docker run --rm -it -v $(pwd):/data netzob/netzob


Configuration of Log Level

Environment variable `NETZOB_LOG_VERBOSITY` can be use to set the logging level. The numeric values of logging levels are given in the Python Documentation of the Logging Module. For example, the following command starts netzob in DEBUG mode:

$ NETZOB_LOG_LEVEL=10 ./netzob

Configuration requirements for Network and PCAP input

Capturing data from network interfaces often requires admin privileges. Before we provide a cleaner and secure way (see issue 425 on the bugtracker for updated information -, a possible HACK is to provide additional capabilities to the python binary:

$ sudo setcap cap_net_raw=ep /usr/bin/python3.XX

Configuration requirements for IPC input on Ubuntu

The following command must be triggered before collecting IPC exchanges with Netzob on Ubuntu (see

$ sudo bash -c "echo 0 > /proc/sys/kernel/yama/ptrace_scope"


The folder doc/documentation contains all the documentation of Netzob.

The user manual can be generated based on RST sources located in folder doc/documentation/source with the following commands:

$ sphinx-apidoc -T -e -f -o doc/documentation/source/developer_guide/API/ src/netzob/
$ find doc/documentation/source/developer_guide/API/ -type f -exec sed -i ':a;N;$!ba;s/Subpackages\n-----------\n\n.. toctree::\n/Subpackages\n-----------\n\n.. toctree::\n    :maxdepth: 1\n    /g' {} +
$ sphinx-build -b html doc/documentation/source/ doc/documentation/build/

An up-to-date version of the documentation is hosted on the Read The Docs platform.


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.

These operations are detailed on Netzob’s wiki through the following pages:

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.


v1.0.2 – 2016-04-30

Version name:StompingFrilledShark
  • major improvement
    • global improvement of code architecture and organization
    • enable custom operations on fields values
    • a list of valid bytes can be specified to specify a subset of values a domain accepts
    • add SendReceived() method in all channels to simplify trafic generation
    • add traffic rate and duration constraints in channels and abstraction layer
    • new channel ‘RawEthernetClient’ to send raw Ethernet frames
    • new channel ‘IPClient’ to send raw IP frames
    • the Protocol class can load ZDL format and automata files
    • introduces Pseudo Field: a field used in the computation of another field but dont produce real content
  • minor improvement
    • pcap importer can merge consecutives messages with same source and destination to mimic a flow
    • improve unit-tests on relationship finder
    • an AbstractMessage stores the type of message
    • remove typechecking in channel write() methods to allow better performances
    • presets can be used when using AbstractionLayer
    • increase default maximum data size to 65535 * 8 (i.e. 65535 bytes)
  • major bug fix
    • fix symbol display when messages includes exotic encoded bytes
    • fix InternetChecksum computation
    • fix size field computation to allow payload of size > 23535 bytes
    • fix size field computation that depends on Repeat variable
    • fix InternetChecksum CRC computation to support bitarrays structures
  • minor bug fix
    • remove nbUnits from Integer class
    • remove the layer attribute of Fields
    • fix the identification of data-type relationships
    • convert snippets in the documentation to python3

v1.0.1 – 2017-03-05

Version name:StompingFrilledShark
  • minor improvement
    • Improves code style (mostly PEP8 constraints)
    • File Importer
    • On-demand performance tests for parallel alignment (de)activation
    • Ensures determinism of ClusterBySize clustering method
    • Base64 and Zlib Encoding functions
  • minor bug fix
    • Updates Copyright dates in source headers
    • Removes obsolete Rep module

v1.0 – 2017-02-03

Version name:StompingFrilledShark
  • major improvement
    • “FlowParser” to parse a succession of message made of different symbols
    • large test campaign created to ensure netzob’s quality
    • migration to python3
    • add SSL client and server channels
    • improve package hierarchy
  • minor improvement
    • enable travis supervision
    • measure test coverage
    • Entropy measurement methods
    • support for timestamps detection
    • improve size field detection algorithm
    • enable RAWIP channels
    • network pcap importer supports ICMP message
  • major bug fix
    • various bug fixes
    • multiple bug fixes in C alignment methods
  • minor bug fix
    • fix Symbol comparison methods
    • fix logging verbosity
    • remove useless codes and resources

v0.4.1 – 2013-02-02

Version name:WaddlingPeccary
  • Export plugins
    • Automatic generation of Wireshark dissectors
    • Automatic generation of Peach fuzzers
  • Workspaces and projects
    • Workspace manager
    • Project manager
    • Trace manager
  • Pretty print of XML files
  • Simplify the default Variable
  • Provide extra compile arguments to the build process

v0.4 – 2012-11-15

Version name:JumpingRhino
  • User interface
    • New user-friendly graphical interface
    • Port Netzob to GTK+3
    • Allow specification of logging level in the UI
  • New plugin architecture
  • Internationalization of Netzob
  • Vocabulary inference
    • Support of layers
    • Support customized transformation functions
    • Provide the edition of a variable
    • Support IPv4, MAC and random binary variables
    • Support filters for displayed messages
    • Allow export of a selection of fields as a new symbol
  • Import
    • Importer for OSpy projects
    • Allow user to specify the import layer (2,3 or 4) while importing network messages
    • Allow to keep delimiter while file importing. Indicate the position of the delimiter
  • Automatic Bug Reporter

v0.3.3 – 2012-06-06

Version name:FlyingRazorback
  • Graphical interface
    • Visualization and encoding filters
    • Mathematical filters (Base64, GZIP, BZ2)
    • Dedicated Search View
    • Preview of data rendering in contextual menu
    • Support format visualization at the symbol level
  • Partitioning
    • Alignment and sequencing by field
    • Execute alignment on specified symbols
    • Split field by the right
    • Allow the partitioning of messages with specified boundaries
    • Allow partitioning at the project and symbol level
    • Similarity score based on number of common dynamic elements
    • Optimization of Needleman : don’t repeat the same computation twice
    • Implement native UPGMA algorithm
  • Grammar inference
    • Infer the grammar of a network client
  • Project/trace management
    • Export / Import projects
    • Importer for XML formated traces

v0.3.2 – 2012-02-23

  • Upgrade Vocabulary Inference
    • Add Octal visualization
      • Feature #57: Resize columns
      • Feature #59: Allows to copy message/field to clipboard
      • Feature #60: Support simple alignment
      • Feature #62: Allow the deletion of multiple messages at a time
      • Feature #20: Show the current status of an alignment
      • Manual modification of the Regex of a field
    • Upgrade Grammar Inference
      • Feature #55: Dedicated GUI for the automatic inferring process
    • Upgrade Simulator
      • Feature #87: Specify source port for network simulator
  • Upgrade Import/Export and Traces Management
    • Feature #22: Activate the management of traces
    • Feature #61: Traces must be compressed when stored in the trace manager
    • Feature #92: Handle cooked socket (SLL) packet format
    • Feature #83: Support of human readable format export
    • Support Unicode for filenames
  • Extra
    • Workspace can be specified through a command line argument
    • Feature #73: Add manpage for Netzob
    • Feature #74: Add “.desktop” file in the official version
    • Apply pep8 quality repository on source code

v0.3.1 – 2012-01-12

  • Small fixes

v0.3 – 2012-01-12

  • Upgraded GUI and user experience
    • Add a menu
    • Simplify the Vocabulary inference panel
    • Add Workspaces and Projects definitions
  • Upgrade Vocabulary Inference
    • Add alignment based on an arbitrary delimitor
    • Identification of the definition domain of a field
    • Add support for environmental dependencies
    • Add new visualization of data encoding
      • Format: hex, string and binary
      • Unit size: bit, 8-bits, 16-bits, 32-bits and 64-bits
      • Sign: signed and unsigned
      • Endianess: big and little endian
    • Add concept of variable :
      • Include Binary Value
      • Include Word Value
      • Include Aggregate Value
      • Include Alternate Value
  • Add grammar inference module
    • Add the definition of the MMSTD model
    • Implementation of the Angluin L* algorithm
    • Implementation of the W-Method Algorithm
    • Add an alpha version of the automatic inferring process
  • Add simulation module
    • Supports Network Server and Client simulations
  • Add import modules : files and library calls
    • Add multiple files import
  • Extra

v0.2 – 2011-09-01

  • Add import modules : IPC, PCAP and Live network flows
  • Add export module : raw XML format
  • Improvement of Needleman and Wunsh performance with OpenMP

v0.1 – 2011-08-16

  • Initial release

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