Typestate-Guided Fuzzer for Discovering Use-after-Free Vulnerabilities

Haijun Wang, Xiaofei Xie, Yi Li, Cheng Wen, Yuekang Li, Yang Liu, Shengchao Qin, Hongxu Chen, Yulei Sui

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Existing coverage-based fuzzers usually use the individual control flow graph (CFG) edge coverage to guide the fuzzing process, which has shown great potential in finding vulnerabilities. However, CFG edge coverage is not effective in discovering vulnerabilities such as use-after-free (UaF). This is because, to trigger UaF vulnerabilities, one needs not only to cover individual edges, but also to traverse some (long) sequence of edges in a particular order, which is challenging for existing fuzzers. To this end, we propose to model UaF vulnerabilities as typestate properties, and develop a typestate-guided fuzzer, named UAFL, for discovering vulnerabilities violating typestate properties. Given a typestate property, we first perform a static typestate analysis to find operation sequences potentially violating the property. Our fuzzing process is then guided by the operation sequences in order to progressively generate test cases triggering property violations. In addition, we also employ an information flow analysis to improve the efficiency of the fuzzing process. We have performed a thorough evaluation of UAFL on 14 widely-used real-world programs. The experiment results show that UAFL substantially outperforms the state-of-the-art fuzzers, including AFL, AFLFast, FairFuzz, MOpt, Angora and QSYM, in terms of the time taken to discover vulnerabilities. We have discovered 10 previously unknown vulnerabilities, and received 5 new CVEs.
Original languageEnglish
Title of host publication42nd International Conference on Software Engineering (ICSE 2020)
ISBN (Electronic)9781450371216
Publication statusAccepted/In press - 1 May 2020
Event42nd International Conference on Software Engineering - Seoul, Korea, Republic of
Duration: 5 Oct 202011 Oct 2020
Conference number: ICSE 2020


Conference42nd International Conference on Software Engineering
Country/TerritoryKorea, Republic of
Internet address


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