SoK: You Find What You Seek: Rethinking Oracles, Guidance, and Input Generation in Hardware Fuzzing

Abstract: Hardware fuzzing is an active area in security verification research, yet its industrial adoption remains in its early stages. This SoK examines which lessons from software fuzzing carry over to hardware and where unique approaches are needed. By analyzing 52 fuzzers across RTL/IP, CPU, NoC, and SoC designs, we introduce an analytical framework that frames verification as a bounded search. This search is defined by its objective, oracle, guidance, input generation, target abstraction, and budget. Consequently, a campaign only uncovers failures it can effectively reach, recognize, and prioritize before exhausting its resources. We distinguish two roles for hardware fuzzing: (1) augmenting constrained-random verification (CRV) via feedback-guided coverage and (2) directed adversarial testing based on threat models and security specifications. Through our framework, we identify what each campaign can observe and generate, providing a basis for assessing the evidence behind reported results. Our analysis suggests that mainstream adoption of hardware fuzzing will require reusable interfaces, target-specific verification assets, reproducible evaluations, and transparent reporting of cost and user effort.