If you are involved in vulnerability research, reverse engineering or penetration testing, I suggest to try out the Python programming language. It has a rich set of useful libraries and programs. This page lists some of them.
Most of the listed tools are written in Python, others are just Python bindings for existing C libraries, i.e. they make those libraries easily usable from Python programs.
Some of the more aggressive tools (pentest frameworks, bluetooth smashers, web application vulnerability scanners, war-dialers, etc.) are left out, because the legal situation of these tools is still a bit unclear in Germany -- even after the decision of the highest court. This list is clearly meant to help whitehats, and for now I prefer to err on the safe side.
- Scapy: send, sniff and dissect and forge network packets. Usable interactively or as a library
- pypcap, Pcapy and pylibpcap: several different Python bindings for libpcap
- libdnet: low-level networking routines, including interface lookup and Ethernet frame transmission
- dpkt: fast, simple packet creation/parsing, with definitions for the basic TCP/IP protocols
- Impacket: craft and decode network packets. Includes support for higher-level protocols such as NMB and SMB
- pynids: libnids wrapper offering sniffing, IP defragmentation, TCP stream reassembly and port scan detection
- Dirtbags py-pcap: read pcap files without libpcap
- flowgrep: grep through packet payloads using regular expressions
- Knock Subdomain Scan, enumerate subdomains on a target domain through a wordlist
- Mallory, extensible TCP/UDP man-in-the-middle proxy, supports modifying non-standard protocols on the fly
- Pytbull: flexible IDS/IPS testing framework (shipped with more than 300 tests)
- Paimei: reverse engineering framework, includes PyDBG, PIDA, pGRAPH
- Immunity Debugger: scriptable GUI and command line debugger
- mona.py: PyCommand for Immunity Debugger that replaces and improves on pvefindaddr
- IDAPython: IDA Pro plugin that integrates the Python programming language, allowing scripts to run in IDA Pro
- PyEMU: fully scriptable IA-32 emulator, useful for malware analysis
- pefile: read and work with Portable Executable (aka PE) files
- pydasm: Python interface to the libdasm x86 disassembling library
- PyDbgEng: Python wrapper for the Microsoft Windows Debugging Engine
- uhooker: intercept calls to API calls inside DLLs, and also arbitrary addresses within the executable file in memory
- diStorm: disassembler library for AMD64, licensed under the BSD license
- python-ptrace: debugger using ptrace (Linux, BSD and Darwin system call to trace processes) written in Python
- vdb / vtrace: vtrace is a cross-platform process debugging API implemented in python, and vdb is a debugger which uses it
- Androguard: reverse engineering and analysis of Android applications
- Capstone: lightweight multi-platform, multi-architecture disassembly framework with Python bindings
- PyBFD: Python interface to the GNU Binary File Descriptor (BFD) library
- Sulley: fuzzer development and fuzz testing framework consisting of multiple extensible components
- Peach Fuzzing Platform: extensible fuzzing framework for generation and mutation based fuzzing (v2 was written in Python)
- antiparser: fuzz testing and fault injection API
- TAOF, (The Art of Fuzzing) including ProxyFuzz, a man-in-the-middle non-deterministic network fuzzer
- untidy: general purpose XML fuzzer
- Powerfuzzer: highly automated and fully customizable web fuzzer (HTTP protocol based application fuzzer)
- SMUDGE
- Mistress: probe file formats on the fly and protocols with malformed data, based on pre-defined patterns
- Fuzzbox: multi-codec media fuzzer
- Forensic Fuzzing Tools: generate fuzzed files, fuzzed file systems, and file systems containing fuzzed files in order to test the robustness of forensics tools and examination systems
- Windows IPC Fuzzing Tools: tools used to fuzz applications that use Windows Interprocess Communication mechanisms
- WSBang: perform automated security testing of SOAP based web services
- Construct: library for parsing and building of data structures (binary or textual). Define your data structures in a declarative manner
- fuzzer.py (feliam): simple fuzzer by Felipe Andres Manzano
- Fusil: Python library used to write fuzzing programs
- Requests: elegant and simple HTTP library, built for human beings
- HTTPie: human-friendly cURL-like command line HTTP client
- ProxMon: processes proxy logs and reports discovered issues
- WSMap: find web service endpoints and discovery files
- Twill: browse the Web from a command-line interface. Supports automated Web testing
- Ghost.py: webkit web client written in Python
- Windmill: web testing tool designed to let you painlessly automate and debug your web application
- FunkLoad: functional and load web tester
- spynner: Programmatic web browsing module for Python with Javascript/AJAX support
- python-spidermonkey: bridge to the Mozilla SpiderMonkey JavaScript engine; allows for the evaluation and calling of Javascript scripts and functions
- mitmproxy: SSL-capable, intercepting HTTP proxy. Console interface allows traffic flows to be inspected and edited on the fly
- pathod / pathoc: pathological daemon/client for tormenting HTTP clients and servers
- Volatility: extract digital artifacts from volatile memory (RAM) samples
- LibForensics: library for developing digital forensics applications
- TrIDLib, identify file types from their binary signatures. Now includes Python binding
- aft: Android forensic toolkit
- pyew: command line hexadecimal editor and disassembler, mainly to analyze malware
- Exefilter: filter file formats in e-mails, web pages or files. Detects many common file formats and can remove active content
- pyClamAV: add virus detection capabilities to your Python software
- jsunpack-n, generic JavaScript unpacker: emulates browser functionality to detect exploits that target browser and browser plug-in vulnerabilities
- yara-python: identify and classify malware samples
- phoneyc: pure Python honeyclient implementation
- Didier Stevens' PDF tools: analyse, identify and create PDF files (includes PDFiD, pdf-parser and make-pdf and mPDF)
- Opaf: Open PDF Analysis Framework. Converts PDF to an XML tree that can be analyzed and modified.
- Origapy: Python wrapper for the Origami Ruby module which sanitizes PDF files
- pyPDF2: pure Python PDF toolkit: extract info, spilt, merge, crop, encrypt, decrypt...
- PDFMiner: extract text from PDF files
- python-poppler-qt4: Python binding for the Poppler PDF library, including Qt4 support
- InlineEgg: toolbox of classes for writing small assembly programs in Python
- Exomind: framework for building decorated graphs and developing open-source intelligence modules and ideas, centered on social network services, search engines and instant messaging
- RevHosts: enumerate virtual hosts for a given IP address
- simplejson: JSON encoder/decoder, e.g. to use Google's AJAX API
- PyMangle: command line tool and a python library used to create word lists for use with other penetration testing tools
- Hachoir: view and edit a binary stream field by field
- py-mangle: command line tool and a python library used to create word lists for use with other penetration testing tools
- IPython: enhanced interactive Python shell with many features for object introspection, system shell access, and its own special command system
- Beautiful Soup: HTML parser optimized for screen-scraping
- matplotlib: make 2D plots of arrays
- Mayavi: 3D scientific data visualization and plotting
- RTGraph3D: create dynamic graphs in 3D
- Twisted: event-driven networking engine
- Suds: lightweight SOAP client for consuming Web Services
- M2Crypto: most complete OpenSSL wrapper
- NetworkX: graph library (edges, nodes)
- Pandas: library providing high-performance, easy-to-use data structures and data analysis tools
- pyparsing: general parsing module
- lxml: most feature-rich and easy-to-use library for working with XML and HTML in the Python language
- Whoosh: fast, featureful full-text indexing and searching library implemented in pure Python
- Pexpect: control and automate other programs, similar to Don Libes `Expect` system
- Sikuli, visual technology to search and automate GUIs using screenshots. Scriptable in Jython
- PyQt and PySide: Python bindings for the Qt application framework and GUI library
- Violent Python by TJ O'Connor. A Cookbook for Hackers, Forensic Analysts, Penetration Testers and Security Engineers
- Grey Hat Python by Justin Seitz: Python Programming for Hackers and Reverse Engineers.
- Black Hat Python by Justin Seitz
- Python for Secret Agents by Steven F. Lott. Analyze, encrypt, and uncover intelligence data using Python
SecurityTube Python Scripting Expert (SPSE) is an online course and certification offered by Vivek Ramachandran.
The Python Arsenal for Reverse Engineering is a large collection of tools related to reverse engineering.
There is a SANS paper about Python libraries helpful for forensic analysis (PDF).
For more Python libaries, please have a look at PyPI, the Python Package Index.