Chucky: exposing missing checks in source code for vulnerability discovery

Fabian Yamaguchi, Christian Wressnegger, Hugo Gascon, Konrad Rieck

Abstract: Uncovering security vulnerabilities in software is a key for operating secure systems. Unfortunately, only some security flaws can be detected automatically and the vast majority of vulnerabilities is still identified by tedious auditing of source code. In this paper, we strive to improve this situation by accelerating the process of manual auditing. We introduce Chucky, a method to expose missing checks in source code. Many vulnerabilities result from insufficient input validation and thus omitted or false checks provide valuable clues for finding security flaws. Our method proceeds by statically tainting source code and identifying anomalous or missing conditions linked to security-critical objects.In an empirical evaluation with five popular open-source projects, Chucky is able to accurately identify artificial and real missing checks, which ultimately enables us to uncover 12 previously unknown vulnerabilities in two of the projects (Pidgin and LibTIFF).