Adaptive caches as a defense mechanism against cache side-channel attacks

Side-channel attacks exploit architectural features of computing systems and algorithmic properties of applications executing on these systems to steal sensitive information. Cache side-channel attacks are more powerful and practical compared to other classes of side-channel attacks due to several factors, such as the ability to be mounted without physical access to the system. Some secure cache architectures have been proposed to counter side-channel attacks. However, they all incur significant performance overheads. This work explores the viability of using adaptive caches, which are conventionally used as a performance-oriented architectural feature, as a defense mechanism against cache side-channel attacks. We conduct an empirical analysis, starting from establishing a baseline for the attacker's ability to infer information regarding the memory accesses of the victim process when there is no active defense mechanism in place and the attacker is fully aware of all the cache parameters. Then, we analyze the effectiveness of the attack without complete knowledge of the cache configuration. Finally, based on the insight that the success of the attack is heavily dependent on knowledge of the cache configuration, we formulate a cache monitoring and user-defined events detection methodology, implement a generalized run-time cache reconfiguration technique, and observe their effect on successfully detecting and mitigating attacks on the cache subsystem. We observe that reconfiguring different cache parameters during a side-channel attack reduces the accuracy of the attack in detecting cache sets accessed by the victim by 44% on average, with a maximum of 90% reduction.