Abstract: As a specification for the interaction between devices,network protocols play an important role in computer networks.Vulnerabilities in protocol implementation can cause devices to be attacked remotely,which poses a huge security risk.Fuzzing is an important method to discover security vulnerabilities in programs.Before fuzzing of protocols,it is necessary to conduct reverse analysis on them,and generating high-quality testcases under the guidance of protocol format and state machine model.However,in the above process,testcase generation requires manual construction,and the constructed testcase is difficult to cover the deep level state.To solve these problems,this paper proposes an automated testcases generation technology.Defining testcase generation rules in the template,building complete test paths based on the state transition path generation algorithm,and effectively performing fuzzing on protocol programs.Experimental results show that compared with the current advanced protocol fuzzer Boo-fuzz,the number of effective testcases generated by the proposed method can be increased by 51.8%.It is tested in four real software to verify three open vulnerabilities.At the same time,a new flaw is found and confirmed by developers.

Key words: Network protocol, Fuzzing, Testcase generation, Protocol state detection, Vulnerability discovery