Enhancing Fine-Grained Smart Contract Vulnerability Detection Through Domain Features and Transparent Interpretation

Smart contracts, which automatically execute transactions based on predefined conditions, play a crucial role in asset and money exchanges. Due to their involvement in significant financial transactions, these contracts are attractive targets for hackers, leading to substantial financial losses through exploitable vulnerabilities. While various program analysis methods such as Oyente, Mythril, and Securify have been proposed to address these security concerns, they rely on rule-based patterns that are time-consuming to develop and offer limited coverage. Deep learning methods present an alternative by automatically learning code features to detect vulnerabilities. However, existing approaches face critical challenges, including feature limitations and lack of interpretability. To address these gaps, we propose the interpretable smart contract vulnerability detector, a Graph Isomorphism Network (GIN)-based vulnerability prediction model for smart contracts, enhanced with code subgraph explanations. Our approach identifies and incorporates 43 domain-specific features, augmenting GIN with domain knowledge attention mechanisms to improve vulnerability prediction. In addition, we develop an interpreter called SubgraphV, which provides explanations for vulnerability predictions through interpreted subgraphs. Our model demonstrates superior performance over traditional tools, achieving F1 score improvements from 0.254 to 0.489 on a dataset of 103 smart contract function vulnerabilities. SubgraphV outperforms existing explainability methods like GNNexplainer, PGExplainer, and SubgraphX in pinpointing vulnerabilities, accurately reflecting vulnerability patterns, and enhancing the understanding of vulnerabilities.