DAGguise Aims to Protect Programs Against Side-Channel Attacks Without Tanking Performance
Designed to "shape" memory access so as to make it immune to interpretation, DAGguise is 12 percent faster than its rivals.
A team of researchers at the Massachusetts Institute of Technology (MIT) have demonstrated an approach to protecting computer systems against memory timing side-channel attacks, which is around 12 percent faster than rival protections — helping to mitigate the performance penalty that comes with increased protection.
Side-channel attacks, including the most well-known Spectre and Meltdown, allow unprivileged programs running on a processor to spy on supposedly-protected programs — using hardware techniques introduced to improve performance to infer the contents of protected memory and make off with private cryptographic keys and more. Mitigating against these attacks typically means disabling or bypassing the performance-boosting functions in question, lowering performance — but DAGguise comes with the promise of a big speed boost over its rival protection systems.
"Nowadays, it is very common to share a computer with others, especially if you are do computation in the cloud or even on your own mobile device," explains senior author Mengjia Yan, professor electrical engineering and computer science, of the problem DAGguise tries to solve. "A lot of this resource sharing is happening. Through these shared resources, an attacker can seek out even very fine-grained information."
"DAGguise [is] a defense mechanism which fully protects against memory timing side channels while allowing for dynamic traffic contention in order to achieve good performance," the researchers write in the abstract to their paper. "DAGguise utilizes a novel abstract memory access representation, the Directed Acyclic Request Graph (𝑟 DAG for short), to model memory access patterns which experience contention. DAGguise shapes a victim’s memory access patterns according to a publicly known 𝑟 DAG obtained through a lightweight profiling stage, completely eliminating information leakage."
DAGguise is far from the only way to eliminate memory timing side channel attacks, but could well be the fastest: In simulation testing the team found that it offered a 12 percent speed boost over its state-of-the-art rival Fixed Service, and up to a 20 percent relative performance increase for applications co-located on the same processor which do not require protection.
The paper detailing DAGguise is available under open-access terms as a PDF download from MIT's CSAIL; source code for DAGguise itself has been published to GitHub under a permissive licence.