Protecting COTS Binaries from Disclosure-guided Code Reuse Attacks.

Code diversification, combined with execute-only memory, provides an effective defense against just-in-time code reuse attacks. However, existing techniques for combining code diversification and hardware-assisted memory protections typically require compiler support, as well as the deployment or modification of a hypervisor. These requirements often cannot be met, either because source code is not available, or because the required hardware features may not be available on the target system. In this paper we present SECRET, a software hardening technique tailored to legacy and closed-source software that provides equivalent protection to execute-only memory without relying on hardware features or recompilation. This is achieved using two novel techniques, code space isolation and code pointer remapping, which prevent read accesses to the executable memory of the protected code. Furthermore, SECRET thwarts code pointer harvesting attacks on ELF files by remapping existing code pointers to use random values. SECRET has been implemented on 32-bit Linux systems. Our evaluation shows that it introduces just 2% additional runtime overhead on top of a state-of-the-art CFI implementation, bringing the total average overhead to about 16%. In addition, it achieves better protection coverage compared to compiler-based techniques, as it can handle low-level machine code such as inline assembly or extra code introduced by the linker and loader.