Evaluating the Effectiveness of Decompilers

In software security tasks like malware analysis and vulnerability mining, reverse engineering is pivotal, with C decompilers playing a crucial role in understanding program semantics. However, reverse engineers still predominantly rely on assembly code rather than decompiled code when analyzing complex binaries. This practice underlines the limitations of current decompiled code, which hinders its effectiveness in reverse engineering. Identifying and analyzing the problems of existing decompilers and making targeted improvements can effectively enhance the efficiency of software analysis. In this study, we systematically evaluate current mainstream decompilers’ semantic consistency and readability. Semantic evaluation results show that the state-of-the-art decompiler Hex-Rays has about 55% accuracy at almost all optimization, which contradicts the common belief among many reverse engineers that decompilers are usually accurate. Readability evaluation indicates that despite years of efforts to improve the readability of the decompiled code, decompilers’ template-based approach still predominantly yields code akin to binary structures rather than human coding patterns. Additionally, our human study indicates that to enhance decompilers’ accuracy and readability, introducing human or compiler-aware strategies like a speculate-verify-correct approach to obtain recompilable decompiled code and iteratively refine it to more closely resemble the original binary, potentially offers a more effective optimization method than relying on static analysis and rule expansion.