Fault Injection Characterization on Modern CPUs

Abstract

Recently, several Fault Attacks (FAs) which target modern Central Processing Units (CPUs) have emerged. These attacks are studied from a practical point of view and, due to the modern CPUs complexity, the underlying fault effect is usually unknown. In this article, we focus on the characterization of a perturbation (the fault model) on modern CPU. For that, we introduce the first approach to characterize the fault model on modern CPU from the Instruction Set Architecture (ISA) level to the micro-architectural level. This fault model helps at determining which micro-architecture elements are disrupted and how. Our fault model aims at finding original attack paths and design efficient countermeasures. To confront our approach to real modern CPUs, we apply our approach on ARM and x86 architectures CPUs, mainly on the BCM2837 and an Intel Core i3.

Electromagnetic fault injection against a complex CPU, toward new micro-architectural fault models

“…Moreover, this fault model matches the observation made by Trouchkine et al in [21]. In this work, the authors characterize a fault model while perturbing a BCM2837 using EMFI.…”

“…The initial goal was to try to modify register values to see if we could confirm the fault model as in [21]. Instead, we observed an original behavior described in this section.…”

“…Characterizing fault effects on complex CPUs is a hot topic to improve their hardware security; for instance, to prevent attacks by implementing efficient countermeasures. Few works [14,21] focus on this research area.…”

“…To complete this approach, Trouchkine et al [21] propose a model for complex CPUs and a method to obtain micro-architectural information on the fault from observations at the ISA level. By using this method, the authors are able to identify the defects that appear in the registers, pipeline or cache of an x86 CPU and an ARM CPU.…”

“…However, the obtained fault model cannot be scaled up on complex CPUs embedded in SoCs due to the latter's hardware complexity. Some recent papers [14,21] have proposed fault characterizations on complex CPUs. However, since they use a device running a complex operating system (OS), their analysis cannot precisely infer the impact on microarchitectural elements.…”