Vulnerabilities related to option combinations pose a significant challenge
in software security testing due to their vast search space. Previous research
primarily addressed this challenge through mutation or filtering techniques,
which inefficiently treated all option combinations as having equal potential
for vulnerabilities, thus wasting considerable time on non-vulnerable targets
and resulting in low testing efficiency. In this paper, we utilize carefully
designed prompt engineering to drive the large language model (LLM) to predict
high-risk option combinations (i.e., more likely to contain vulnerabilities)
and perform fuzz testing automatically without human intervention. We developed
a tool called ProphetFuzz and evaluated it on a dataset comprising 52 programs
collected from three related studies. The entire experiment consumed 10.44 CPU
years. ProphetFuzz successfully predicted 1748 high-risk option combinations at
an average cost of only \8.69perprogram.Resultsshowthatafter72hoursoffuzzing,ProphetFuzzdiscovered364uniquevulnerabilitiesassociatedwith12.30%ofthepredictedhigh−riskoptioncombinations,whichwas32.85%higherthanthatfoundbystate−of−the−artinthesametimeframe.Additionally,usingProphetFuzz,weconductedpersistentfuzzingonthelatestversionsoftheseprograms,uncovering140vulnerabilities,with93confirmedbydevelopersand21awardedCVEnumbers.