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

Abstract

The last years have seen the emergence of fault attacks targeting modern central processing units (CPUs). These attacks are analyzed at a very high abstraction level and, due to the modern CPUs complexity, the underlying fault effect is usually unknown. Recently, a few articles have focused on characterizing faults on modern CPUs.In this article, we focus on the electromagnetic fault injection (EMFI) characterization on a bare-metal implementation. With this approach, we discover and understand new effects on micro-architectural subsystems. We target the BCM2837 where we successfully demonstrate persistent faults on L1 instruction cache, L1 data cache and L2 cache. We also show that faults can corrupt the memory management unit (MMU). To validate our fault model, we realize a persistent fault analysis to retrieve an AES key.

EM Fault Model Characterization on SoCs: From Different Architectures to the Same Fault Model

“…This paper introduces the characterization method we use in our work. Additionally, to these works, which mainly focus on a characterization at the Instruction Set Architecture (ISA) level, a characterization of the micro-architectural behaviour of a BCM2837 against EMFI has been done in [11] with an exploitation on the AES algorithm using a Persistent Fault Analysis (PFA). In this work, the authors target only one architecture.…”

“…The drawback of this computational power is a complex hardware layout which is, for now, lacking security analysis, in particular, regarding hardware attacks. However, some recent works have demonstrated that these attacks are efficient to lower the security of modern SoCs [5], [11], [12], [13]. Therefore, we believe it is important to understand the underlying effect induced by the proposed perturbations to be able to measure their impact and design adapted countermeasures.…”

“…Therefore, we believe it is important to understand the underlying effect induced by the proposed perturbations to be able to measure their impact and design adapted countermeasures. The used injection mediums were the laser [13], the Rowhammer attack [12] and the ElectroMagnetic Fault Injection (EMFI) [11].…”

The Forgotten Threat of Voltage Glitching: A Case Study on Nvidia Tegra X2 SoCs

“…However, faults can not only be induced by glitching the supply voltage. In the past couple of years, EM fault injection techniques against modern CPUs have been examined to inject faults in a targeted and contactless way [8], [47]. Consequently, a holistic view is necessary to prevent all kinds of fault injection attacks that can manipulate the behavior of the target device.…”

“…Next to the intended corruption of data values, faults can be used to skip security checks, enter protected code paths, or gain code execution [4], [5]. During the past years, attacks against microcontrollers and SoCs using laser-based [6] and electromagnetic [7], [8] FI have been presented. While these techniques offer high accuracy in targeting a specific part of the chip, they also require comparatively sophisticated setups.…”