Frequency Throttling Side-Channel Attack

TL;DR

This paper reveals that dynamic CPU frequency adjustments, used for power management, can leak timing information that enables attackers to recover secret cryptographic keys, compromising system security.

Contribution

It introduces a novel frequency throttling side-channel attack exploiting power management behavior to infer secret data, validated on AES encryption across multiple systems.

Findings

Attack successfully recovers entire AES key bytes

Effective across different systems and threat models

Highlights need for mitigation strategies

Abstract

Modern processors dynamically control their operating frequency to optimize resource utilization, maximize energy savings, and conform to system-defined constraints. If, during the execution of a software workload, the running average of any electrical or thermal parameter exceeds its corresponding predefined threshold value, the power management architecture will reactively adjust CPU frequency to ensure safe operating conditions. In this paper, we demonstrate how such power management-based frequency throttling activity forms a source of timing side-channel information leakage, which can be exploited by an attacker to infer secret data even from a constant-cycle victim workload. The proposed frequency throttling side-channel attack can be launched by both kernel-space and user-space attackers, thus compromising security guarantees provided by isolation boundaries. We validate our attack methodology across different systems and threat models by performing experiments on a constant-cycle implementation of AES algorithm based on AES-NI instructions. The results of our experimental evaluations demonstrate that the attacker can successfully recover all bytes of an AES key by measuring encryption execution times. Finally, we discuss different options to mitigate the threat posed by frequency throttling side-channel attacks, as well as their advantages and disadvantages.