PhD Dissertation Proposal by LIN Yan | Novel Techniques in Recovering, Embedding, and Enforcing Policies for Control-Flow Integrity

Novel Techniques in Recovering, Embedding, and Enforcing Policies for Control-Flow Integrity

About The Talk

Control-Flow Integrity (CFI) is an attractive security property with which most injected and code-reuse attacks can be defeated, including advanced attacking techniques like Return-Oriented Programming (ROP). There are three fundamental components in CFI enforcement. The first component is accurately recovering the policy (CFG). Usually, the more precise the policy (CFG) is, the more security CFI improves, but precise CFG generation was considered hard without the support of source code. The second one is embedding the CFI policy securely. Current CFI enforcement usually inserts checks before indirect branches to consult a read-only table which stores the valid CFG information. However, this kind of read-only table can be overwritten by some kinds of attacks. The third component is to efficiently enforce the CFI policy. In current approaches, no matter whether there are attacks, the CFI checks are always executed whenever there is an indirect control flow transfer. Therefore, it is critical to minimize the performance impact of the CFI checks.

In this proposal, we propose novel solutions to handle these three fundamental components. To generate a precise CFI policy without the support of the source code, we systematically study two methods which recover CFI policy based on function signature matching at the binary level and propose our novel rule- and heuristic-based mechanism to more accurately recover function signature. To embed CFI policy securely, we design a novel platform which encodes the policy into the machine instructions directly without relying on consulting any read-only data structure by making use of the idea of instruction-set randomization. In it, each basic block is encrypted with a key derived from the CFG. To efficiently enforce CFI policy, we make use of a mature dynamic code optimization platform called DynamoRIO to enforce the policy so that it only requires to do the CFI check when needed.

Speaker Biography

Yan Lin is a PhD candidate in Cybersecurity at School of Information Systems, Singapore Management University. She is advised by Associate Professor Debin Gao. Her research focuses on software security and system security.