Fault injection attacks represent an effective threat to embedded systems. Recently, Laurent et al. have reported that fault injection attacks can leverage faults inside the microarchitecture. However, state-of-the-art countermeasures, hardware-only or with hardware support, do not consider the integrity of microarchitecture control signals that are the target of these faults. We present MAFIA, a microarchitecture protection against fault injection attacks. MAFIA ensures integrity of pipeline control signals through a signature-based mechanism, and ensures fine-grained control-flow integrity with a complete indirect branch support and code authenticity. We analyze the security properties of two different implementations with different security/overhead tradeoffs: one with a CBC-MAC/Prince signature function, and another one with a CRC32. We present our implementation of MAFIA in a RISC-V processor, supported by a dedicated compiler toolchain based on LLVM/Clang. We report a hardware area overhead of 23.8% and 6.5% for the CBC-MAC/Prince and CRC32, respectively. The average code size and execution time overheads are 29.4% and 18.4%, respectively, for the CRC32 implementation and are 50% and 39% for the CBC-MAC/Prince.

Fault injection attacks have become a serious threat against embedded systems. Recently, Laurent et al. have reported that some faults inside the microarchitecture escape all typical software fault models and so software counter-measures. Moreover, state-of-the-art counter-measures, hardware-only or with hardware support, do not consider the integrity of microarchitectural control signals that are the target of these faults. We present SCI-FI, a counter-measure for Control Signal, Code, and Control-Flow Integrity against Fault Injection attacks. SCI-FI combines the protection of pipeline control signals with a fine-grained code and control-flow integrity mechanism, and can additionally provide code authentication. We evaluate SCI-FI by extending a RISC-V core. The average hardware area overheads range from 6.5% to 23.8%, and the average code size and execution time increase by 25.4% and 17.5% respectively.