Trading Off a Vulnerability: Does Software Obfuscation Increase the Risk of ROP Attacks

Software obfuscation is a commonly used technique to protect software, especially against reverse-engineering attacks. It is a form of security through obscurity and is commonly used for intellectual property and Digital Rights Management protection. However, this increase of security may come at the expense of increased vulnerabilities in another direction, hitherto unsuspected. In this paper, we propose and investigate the hypothesis that some of the most popular obfuscation techniques, including changing the control flow graph and substituting simpler instruction sequences with complex instructions, may make the obfuscated binary more vulnerable to Return-Oriented Programming (ROP) based attacks. ROP is a comparatively recent technique used to exploit buffer-overflow vulnerabilities. We analyze the ROP gadgets present in both obfuscated and un-obfuscated versions of well known binaries. We show that the number of ROP gadgets in a binary significantly increase after certain obfuscations, and it can potentially make ROP-based exploits easier.