Sequence Coverage Directed Greybox Fuzzing

Existing directed fuzzers are not efficient enough. Directed symbolic-execution-based whitebox fuzzers, e.g. BugRedux, spend lots of time on heavyweight program analysis and constraints solving at runtime. Directed greybox fuzzers, such as AFLGo, perform well at runtime, but considerable calculation during instrumentation phase hinders the overall performance. In this paper, we propose Sequence-coverage Directed Fuzzing (SCDF), a lightweight directed fuzzing technique which explores towards the user-specified program statements efficiently. Given a set of target statement sequences of a program, SCDF aims to generate inputs that can reach the statements in each sequence in order and trigger bugs in the program. Moreover, we present a novel energy schedule algorithm, which adjusts on demand a seed's energy according to its ability of covering the given statement sequences calculated on demand. We implement the technique in a tool LOLLY in order to achieve efficiency both at instrumentation time and at runtime. Experiments on several real-world software projects demonstrate that LOLLY outperforms two well-established tools on efficiency and effectiveness, i.e., AFLGo–a directed greybox fuzzer and BugRedux–a directed symbolic-execution-based whitebox fuzzer.