Comprehensively and efficiently protecting the heap

Abstract

The goal of this paper is to propose a scheme that provides comprehensive security protection for the heap. Heap vulnerabilities are increasingly being exploited for attacks on computer programs. In most implementations, the heap management library keeps the heap meta-data (heap structure information) and the application's heap data in an interleaved fashion and does not protect them against each other. Such implementations are inherently unsafe: vulnerabilities in the application can cause the heap library to perform unintended actions to achieve control-flow and non-control attacks.Unfortunately, current heap protection techniques are limited in that they use too many assumptions on how the attacks will be performed, require new hardware support, or require too many changes to the software developers' toolchain. We propose Heap Server, a new solution that does not have such drawbacks. Through existing virtual memory and inter-process protection mechanisms, Heap Server prevents the heap meta-data from being illegally overwritten, and heap data from being meaningfully overwritten. We show that through aggressive optimizations and parallelism, Heap Server protects the heap with nearly-negligible performance overheads even on heap-intensive applications. We also verify the protection against several real-world exploits and attack kernels.