SIP Proxy is an Open Source VoIP security test tool which has been developed by the students Philipp Haupt and Matthias H rlimann during their diploma thesis and second student research project at the University of Applied Sciences Rapperswil (www.hsr.ch). Business partner was Compass Security AG in Rapperswil (www.csnc.ch).
In the so called "Proxy Mode", the application acts as a proxy between a VoIP PBX (e.g. Asterisk) and a UA (VoIP hard- or softphone). SIP traffic can be sniffed and dynamically manipulated with the help of regular expressions. Logged SIP messages can be modified and resent. In the "Test Case Mode" predefined security tests which are specified as XML files can be run against a specific target. Fuzzing technology, which is a kind of black-box testing, can be applied to find weak spots in VoIP devices. There are many more specific modules which can be used within such a test case. For example Wordlist- or Bruteforce attacks. While running a test case, feedback is given by displaying a graphical report which can be exported in a printable PDF document afterwards.
With the help of SIP Proxy, several software bugs and configuration faults in specific VoIP devices have already been discovered.