Armor Within: Defending Against Vulnerabilities in Third-Party Libraries

Vulnerabilities in third-party software modules have resulted in severe security flaws, including remote code execution and denial of service. However, current approaches to securing such libraries suffer from one of two problems. First, they do not perform sufficiently well to be applicable in practice and incur high CPU and memory overheads. Second, they are also harder to apply to legacy and proprietary systems when the source code of the application is not available. There is, therefore, a dire need to secure the internal boundaries within an application to ensure vulnerable software modules are not exploitable via crafted input attacks. We present a novel approach to secure third-party software modules without requiring access to the source code of the program. First, using the foundations of language-theoretic security, we build a validation filter for the vulnerable module. Using the foundations of linking and loading, we present two different ways to insert that filter between the main code and the vulnerable module. Finally, using the foundations of ELF-based access control, we ensure any entry into the vulnerable module must first go through the filter. We evaluate our approaches using three known real-world exploits in two popular libraries-libpng and libxml. We were able to successfully prevent all three exploits from executing.