Sensing CPU Voltage Noise Through Electromagnetic Emanations

Abstract

This work proposes sensing CPU voltage noise through wireless electromagnetic (EM) emanations from the CPU. Compared to previous voltage monitoring methodologies, this approach is not intrusive as it does not require direct physical access to the monitored CPU. To prove the effectiveness of this approach, we use EM signal feedback to find the resonant frequency of the CPU power delivery network, and to generate a CPU voltage noise (dI/dt) virus. This study is performed on a modern out-of-order CPU that supports on-chip fine grain voltage monitoring. This on-chip voltage monitoring capability is used to validate the proposed EM methodology.