We introduce a novel Syntax-based Security Testing (SST) framework that uses a protocol specification to effectively perform security testing on text-based communication protocols. A protocol specification of a particular text-based protocol under-tested (TPUT) represents its syntactic grammar and static semantic contracts on the grammar. Mutators written in TXL break the syntactic and semantic constraints of the protocol specification to generate test cases. Different protocol specification testing strategies can be joined together to yield a compositional testing approach. SST is independent of any particular text-based protocols. The power of SST stems from the way it obtains test cases from the protocol specifications. We also use the robust parsing technique with TXL to parse a TPUT. SST has successfully revealed security faults in different text-based protocol applications such as web applications and kOganizer. We also demonstrate SST can mimic the venerable PROTOS Test-Suite: co-http-reply developed by University of Oulu. / Thesis (Ph.D, Computing) -- Queen's University, 2010-04-30 16:01:18.048