Locate, Then Reason: End-to-End Patch Presence Testing in Stripped Binaries

Abstract

Binary patch presence testing (PPT) determines whether a security fix is present in a stripped binary. Prior systems often assume that patch-relevant code is known or successfully matched. Function-level matching is brittle to compilation changes, inlining, finite model context, and missing usage context; moreover, similarity suppresses the patch-sized distinction needed for the verdict. We present PatchAlign, an end-to-end binary PPT workflow, which performs large-scale localization that maximizes recall economically, then the final verdict reasons for patch-specific evidence. PatchAlign uses instruction-aligned retrieval and caller-callee context to accurately locate patch-relevant binary code pieces, then screens the shortlist and compares target binary code with vulnerable and patched references using an LLM. Our experiments indicate that PatchAlign can precisely localize patch-relevant code and determine patch status without a target-location oracle.