Revisiting Fault Adversary Models – Hardware Faults in Theory and Practice

Fault injection attacks are considered as powerful techniques to successfully attack embedded cryptographic implementations since various fault injection mechanisms from simple clock glitches to more advanced techniques like laser fault injection can lead to devastating attacks. Given these critical attack vectors, researchers came up with a long list of dedicated countermeasures to thwart such attacks. However, the security validation of proposed countermeasures is mostly performed on custom adversary models that are often not tightly coupled with the actual physical behavior of available fault injection mechanisms and, hence, fail to model the reality accurately. Furthermore, using custom models complicates comparison between different designs and evaluation results. As a consequence, we aim to close this gap by proposing a simple, generic, and consolidated fault injection adversary model that can be perfectly tailored to existing fault injection mechanisms and their physical behavior in hardware. To demonstrate the advantages, we apply it to a cryptographic primitive and evaluate it based on different attack vectors. We further show that our proposed adversary model can be integrated into the state-of-the-art fault verification tool VerFI. Finally, we provide a discussion on the benefits and differences of our approach compared to already existing evaluation methods.