AntFuzzer: A Grey-Box Fuzzing Framework for EOSIO Smart Contracts

In recent years, vulnerabilities in EOSIO smart contracts (hereafter referred to as contracts) have led to significant financial losses. Grey-box fuzzing, as a lightweight test generation approach, can enhance the security of EOSIO contracts. However, developing a grey-box fuzzer from scratch is time-consuming and requires a deep understanding of EOSIO internals. In this work, we proposed AntFuzzer, the first highly extensible grey-box fuzzing framework for EOSIO contracts. AntFuzzer implements a novel approach that interfaces AFL (American Fuzzy Lop) to conduct AFL-style grey-box fuzzing on EOSIO contracts. Compared to black-box fuzzing tools, AntFuzzer can effectively trigger those hard-to-cover branches. It improved code coverage on 37.5% of contracts in our benchmark dataset. AntFuzzer also provides unified interfaces for developing new detection plugins for emerging vulnerabilities. We implemented six plugins that detected 741 vulnerabilities across 4,616 real-world contracts in large-scale fuzzing experiments, demonstrating AntFuzzer’s effectiveness and efficiency.