SulleyEX: A fuzzer for stateful network protocol

Fuzzing has become one of the most important technologies in the field of network security, and fuzzer also has become an important tool for discovering network vulnerabilities. But for the stateful network protocol fuzzing, most of fuzzers could not effectively cover the state trajectory, and not achieve a good automation. Aiming at the above issues, this paper designs a fuzzer named SulleyEX based on the open source project Sulley. Firstly, the SulleyEX uses finite-state machine to describe the state trajectory of stateful network protocol and further generates sessions automatically. That dramatically enhances the automation of Sulley session management module. In order to improve the optional ability of the fuzzer, the SulleyEX could automatically extract the protocol format based on Sulley’s data presentation module as well as provide an interface to custom fuzz testing data generation algorithm. Comparing with the traditional Sulley, the experimental results highlight that the SulleyEX could successfully discover the same vulnerability, while the SulleyEX achieves higher automation.