HideM: Protecting the Contents of Userspace Memory in the Face of Disclosure Vulnerabilities.

ABSTRACTMemory disclosure vulnerabilities have become a common component for enabling reliable exploitation of systems by leaking the contents of executable data. Previous research towards protecting executable data from disclosure has failed to gain popularity due to large performance penalties and required architectural changes. Other research has focused on protecting application data but fails to consider a vulnerable application that leaks its own executable data. In this paper we present HideM, a practical system for protecting against memory disclosures in contemporary commodity systems. HideM addresses limitations in existing advanced security protections (e.g., fine-grained ASLR, CFI) wherein an adversary discloses executable data from memory, reasons about protection weaknesses, and builds corresponding exploits. HideM uses the split-TLB architecture, commonly found in CPUs, to enable fine-grained execute and read permission on memory. HideM enforces fine-grained permission based on policy generated from binary structure thus enabling protection of Commercial-Off-The-Shelf (COTS) binaries. In our evaluation of HideM, we find application overhead ranges from a 6.5% increase to a 2% reduction in runtime and observe runtime memory overhead ranging from 0.04% to 25%. HideM requires adversaries to guess ROP gadget locations making exploitation unreliable. We find adversaries have less than a 16% chance of correctly guessing a single gadget across all 28 evaluated applications. Thus, HideM is a practical system for protecting vulnerable applications which leak executable data.