Protocol reverse engineering (PRE) aims to infer the protocol formats of unknown protocols. Existing techniques, whether Network-trace based or Execution-trace based methods, face two main limitations: a reliance on the quality and scale of traffic datasets, which often leads to low accuracy and poor generalization; and a failure to adequately consider the multi-format characteristic prevalent in real-world protocols (i.e., the same protocol may support multiple different formats).

To address these challenges, we propose ProbePRE—a PRE tool that performs multi-format extraction on protocol handlers by autonomously generating packets. ProbePRE employs three key techniques: (1) an execution tracing strategy enhanced with implicit data flow analysis to obtain more detailed execution information; (2) constraint extraction methods tailored for different program structures to pass protocol validation; and (3) an innovative constraint combination algorithm to construct effective packets that guide the protocol handler to execute diverse protocol parsing paths. In our experimental evaluation, we compared ProbePRE with 4 state-of-the-art PRE tools in terms of field segmentation accuracy. The results demonstrated that ProbePRE achieved an F1 score of 0.88, significantly outperforming existing methods. Furthermore, evaluations on 6 protocol handlers indicated that ProbePRE attained 83% completeness in multi-format extraction tasks. Notably, in basic block coverage tests, ProbePRE achieved a 67% improvement over traditional traffic dataset methods, which fully validates the effectiveness of its path exploration capabilities.