Cache Bank-Aware Denial-of-Service Attacks on Multicore ARM Processors.

In this paper, we identify that bank contention in the shared last-level cache (LLC) of multicore processors can cause significant execution time slowdown to cross-core victims even when the cache is partitioned. We propose a Cache Bank-Aware Denial-of-Service (DoS) attack, which is specially engineered to induce bank contention. This is accomplished by leveraging publicly available cache bank mapping information on commercial off-the-shelf (COTS) ARM multicore processors to generate a large number of concurrent memory accesses to a particular cache bank. Importantly, this attack can be mounted from the user-space to delay cross-core victims without requiring any special privilege or OS level support. We implement and evaluate the proposed DoS attack on two ARM multicore platforms using both synthetic and real-world workloads as victim tasks. The results show that the proposed Cache Bank-Aware DoS attack causes up to 9.7X slowdown in synthetic workloads and 2.3X slowdown in real-world workloads even when state-of-the-art isolation techniques, namely LLC partitioning and DRAM bandwidth throttling, are used to protect the victim. In other words, the proposed attack can effectively bypass existing DoS attack mitigation techniques. We identify LLC bandwidth throttling and LLC bank partitioning as potential mitigation solutions and discuss their limitations.