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arXiv · 2502.09864

U Can Touch This! Microarchitectural Timing Attacks via Machine Clears

Billy Bob Brumley
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Abstract

Microarchitectural timing attacks exploit subtle timing variations caused by hardware behaviors to leak sensitive information. In this paper, we introduce MCHammer, a novel side-channel technique that leverages machine clears induced by self-modifying code detection mechanisms. Unlike most traditional techniques, MCHammer does not require memory access or waiting periods, making it highly efficient. We compare MCHammer to the classical Flush+Reload technique, improving in terms of trace granularity, providing a powerful side-channel attack vector. Using MCHammer, we successfully recover keys from a deployed implementation of a cryptographic tool. Our findings highlight the practical implications of MCHammer and its potential impact on real-world systems.

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Billy Bob Brumley. 2025-02-14. U Can Touch This! Microarchitectural Timing Attacks via Machine Clears. https://doi.org/10.1145/3672608.3707711

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