ProxyFuzz is a man-in-the-middle non-deterministic network fuzzer written in Python. ProxyFuzz randomly changes (fuzzes) contents on the network traffic. It supports TCP and UDP protocols and can also be configured to fuzz only one side of the communication. ProxyFuzz is protocol agnostic so it can randomly fuzz any network communication.
ProxyFuzz is a good tool for quickly testing network protocols and provide with basic proof of concepts. Using this tool you will be amazed by the poor quality of software and you will see clients and servers dying upon unexpected input, just be prepared to see the very weird behaviours.
Syntax of ProxyFuzz:
ProxyFuzz 0.1, Simple fuzzing proxy by Rodrigo Marcos
python proxyfuzz -l <localport> -r <remotehost> -p <remoteport> [options]
-w: Number of requests to send before start fuzzing
-c: Fuzz only client side (both otherwise)
-s: Fuzz only server side (both otherwise)
-u: UDP protocol (otherwise TCP is used)
-v: Verbose (outputs network traffic)
-h: Help page
A demo of ProxyFuzz is available here.
The video shows ProxyFuzz proxying traffic between a VMWare Console and a VMWare Server. This is just a dumb example of the things you can do with this tool.
Or read more here.