Pangolin: Incremental Hybrid Fuzzing with Polyhedral Path Abstraction

Hybrid fuzzing, which combines the merits of both fuzzing and concolic execution, has become one of the most important trends in coverage-guided fuzzing techniques. Despite the tremendous research on hybrid fuzzers, we observe that existing techniques are still inefficient. One important reason is that these techniques, which we refer to as non-incremental fuzzers, cache and reuse few computation results and, thus, lose many optimization opportunities. To be incremental, we propose "polyhedral path abstraction", which preserves the exploration state in the concolic execution stage and allows more effective mutation and constraint solving over existing techniques. We have implemented our idea as a tool, namely Pangolin, and evaluated it using LAVA-M as well as nine real-world programs. The evaluation results showed that Pangolin outperforms the state-of-the-art fuzzing techniques with the improvement of coverage rate ranging from 10% to 30%. Moreover, Pangolin found 400 more bugs in LAVA-M and discovered 41 unseen bugs with 8 of them assigned with the CVE IDs.