U Can Touch This! Microarchitectural Timing Attacks via Machine Clears

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.

@article{brumley2025_2502.09864,
  title={ U Can Touch This! Microarchitectural Timing Attacks via Machine Clears },
  author={ Billy Bob Brumley },
  journal={arXiv preprint arXiv:2502.09864},
  year={ 2025 }
}