FormalFuzzer: Formal Verification Assisted Fuzz Testing for SoC Vulnerability Detection

Modern Systems-on-Chips (SoCs) integrate numerous insecure intellectual properties to meet design-cost and time-to-market constraints. Incorporating these SoCs into security-critical systems severely threatens users' privacy. Traditional formal/simulation-based verification techniques detect vulnerabilities to some extent. However, these approaches face challenges in detecting unknown vulnerabilities and suffer from significant manual efforts, false alarms, low coverage, and scalability. Several fuzzing techniques have been developed to mitigate pre-silicon hardware verification limitations. Nevertheless, these techniques suffer from major challenges such as slow simulation platforms, extensive design knowledge requirements, and lacking consideration of untrusted inter-module communications. To overcome these shortcomings, we developed FormalFuzzer, an emulation-based hybrid framework by combining formal verification and fuzz testing, leveraging their own benefits. FormalFuzzer incorporates formal-verification-based pre-processing using templatebased assertion generation to narrow down the search space for fuzz testing and appropriate mutation strategy selection by dynamic feedback derived from a security-oriented cost function. The cost function is developed using vulnerability databases and specifications, indicating the likelihood of triggering a vulnerability. A vulnerability is detected when the cost function reaches global or local minima. Our experiments on RISC-V-based Ariane SoC demonstrate the efficiency of proposed formal-verification-based pre-processing strategies and cost functiondriven feedback on fuzzing in detecting both known and unknown vulnerabilities expeditiously.