Mitigating Timing-Based NoC Side-Channel Attacks With LLC Remapping

Published in IEEE Computer Architecture Letters, 2023

Recent CPU microarchitectural attacks utilize contention over the NoC to mount covert and side-channel attacks on multicore CPUs and leak information from victim applications. We propose NoIR, a dynamic LLC slice selection mechanism using slice remapping to obfuscate interconnect contention patterns. NoIR reduces contention variance by 92.18% and mean IPC degradation due to cache invalidation is limited to 7.38% for SPEC CPU 2017 benchmarks for a 1000-access threshold. While previous defenses focused on redesigning the NoC and routing algorithms, we show that a top-down system-level approach can significantly raise the bar for a NoC security vulnerability with minimal modifications to the NoC hardware.