GSA-Fuzz: Optimize Seed Mutation with Gravitational Search Algorithm

Mutation-based fuzzing is currently one of the most effective techniques to discover software vulnerabilities. It relies on mutation strategies to generate interesting seeds. As a state-of-the-art mutation-based fuzzer, AFL follows a mutation strategy with high randomization, which uses randomly selected mutation operators to mutate seeds at random offsets. Its strategy may ignore some efficient mutation operators and mutation positions. Therefore, in this paper, we propose a solution named GSA-Fuzz to improve the efficiency of seed mutation strategy with the gravitational search algorithm (GSA). GSA-Fuzz uses GSA to learn the optimal selection probability distributions of operators and mutation positions and designs a position-sensitive strategy to guide seed mutation with learned distributions. Besides, GSA-Fuzz also provides a flip mode to calculate the efficiencies of the deterministic stage and indeterministic stage and implements switching between the two stages to further improve the efficiency of seed mutation. We compare GSA-Fuzz with the state-of-the-art fuzzers AFL, MOPT-AFL, and EcoFuzz on 10 open-source programs. GSA-Fuzz finds 145% more paths than AFL, 66% more paths than EcoFuzz, and 43% more paths than MOPT-AFL. In addition, GSA-Fuzz also outperforms other fuzzers in bug detection and line coverage.