SIP Stack Fingerprinting and Stack Difference Attacks presented at BlackhatUSA 2006

by Hendrik Scholz,

Summary : VoIP applications went mainstream, although the underlying protocols are still undergoing constant development. The SIP protocol being the main driver behind this has been analyzed, fuzzed and put to the test before, but interoperability weaknesses still yield a large field for attacks. This presentation gives a short introduction to the SIP protocol and the threats it exposes; enough to understand the issues described. A SIP stack fingerprinting tool will be released during the talk which allows different stacks to be identified and classified for further attacks. The main part focuses on practical attacks targeting features from caller ID spoofing to Lawful Interception. Various attack vectors are pointed out to allow further exploit development.