No 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.

A fault attack is a well-known technique where the behaviour of a chip is voluntarily disturbed by hardware means in order to undermine the security of the information handled by the target. In this paper, we explore how Electromagnetic fault injection (EMFI) can be used to create vulnerabilities in sound software, targeting a Cortex-M3 microcontroller. Several use-cases are shown experimentally: control flow hijacking, buffer overflow (even with the presence of a canary), covert backdoor insertion and Return Oriented Programming can be achieved even if programs are not vulnerable in a software point of view. These results suggest that the protection of any software against vulnerabilities must take hardware into account as well.

Fault Injections (FI) against hardware circuits can make a system inoperable or lead to information security breaches. FI can be used preemptively in order to detect and mitigate weaknesses in a design. FI is an old field of study and therefore numerous techniques and tools can be used for that purpose. Each technique can be used at different levels of circuit design, and has strengths and weaknesses. In this paper, we review these techniques to show their pros and cons and more precisely we highlight their shortcomings with respect to the complexity of modern systems.