An Attack on The Speculative Vectorization: Leakage from Higher Dimensional Speculation

Sayinath Karuppanan, Samira Mirbagher Ajorpaz

This paper argues and shows that speculative vectorization, where a loop with rare or unknown memory dependencies are still vectorized, is fundamentally vulnerable and cannot be mitigated by existing defenses. We implement a simple proof of concept and show the leakage in Apple M2 SoC. We describe the source of leakage using Microarchitectural Leakage Descriptors MLD and we additionally describe principles to extend MLD for other optimization. Also as part of implementation we reverse engineer the M2 cache size and use threaded timer to differentiate between cache hit and miss.

picture_as_pdf flag

Knowledge Graph

arrow_drop_up

Comments

Sign up or login to leave a comment