PLC-Bin2Src: Retrieving Corresponding Structured Text Source Files for PLC Binaries

RESUMO

PLC developers reuse existing components and third-party libraries to reduce the cost of developing new applications, but this reuse can also introduce security risks. When components are distributed only in binary form, provenance tracing, vulnerability assessment, and security auditing become more difficult. To support these analyses, binary2source matching can retrieve the corresponding Structured Text (ST) source file for a PLC binary from a candidate source repository. However, due to the properties of PLC software, this task faces three challenges: cross-platform compilation heterogeneity, a binary-source representation gap, and inadequate representations of PLC semantics. Therefore, we present PLC-Bin2Src, a cross-platform binary2source matching framework that retrieves corresponding ST source files for binaries produced by CODESYS, GEB, OpenPLC v2, and OpenPLC v3. First, PLC-Bin2Src uses platform-aware binary frontends to recover user control logic across toolchains. Then, ST-to-C conversion and shared normalization are used to reduce syntactic differences between source- and binary-side representations. Next, control-data flow graphs (CDFGs) and function call graphs (FCGs) are constructed to capture program semantics, while recovered symbols provide complementary identity evidence. Finally, PLC-Bin2Src compares these representations and combines their similarity scores to rank source candidates. We evaluate PLC-Bin2Src on PLC-BEAD. The results show that PLC-Bin2Src achieves 95.89% Recall@1, 99.66% Recall@5, and an MRR of 0.9769 across four PLC platforms.