DVFS Frequently Leaks Secrets: Hertzbleed Attacks Beyond SIKE, Cryptography, and CPU-Only Data

Abstract

The recent Hertzbleed disclosure demonstrates how remote-timing analysis can reveal secret information previously only accessible to local-power analysis. At worst, this constitutes a fundamental break in the constant-time programming principles and the many deployed programs that rely on them. But all hope is not lost. Hertzbleed relies on a coarse-grained, noisy channel that is difficult to exploit. Indeed, the Hertzbleed paper required a bespoke cryptanalysis to attack a specific cryptosystem (SIKE). Thus, it remains unclear if Hertzbleed represents a threat to the broader security ecosystem.In this paper, we demonstrate that Hertzbleed’s effects are wide ranging, not only affecting cryptosystems beyond SIKE, but also programs beyond cryptography, and even computations occurring outside the CPU cores. First, we demonstrate how latent gadgets in other cryptosystem implementations— specifically "constant-time" ECDSA and Classic McEliece— can be combined with existing cryptanalysis to bootstrap Hertzbleed attacks on those cryptosystems. Second, we demonstrate how power consumption on the integrated GPU influences frequency on the CPU—and how this can be used to perform the first cross-origin pixel stealing attacks leveraging "constant-time" SVG filters on Google Chrome.