SURGEON: Performant, Flexible, and Accurate Re-Hosting via Transplantation

Dynamic analysis of microcontroller-based embedded firmware remains challenging. The general lack of source code availability for Commercial-off-the-shelf (COTS) firmware prevents powerful source-based instrumentation and prohibits compiling the firmware into an executable directly runnable by an analyst. Analyzing firmware binaries requires either acquisition and configuration of custom hardware, or configuration of extensive software stacks built around emulators. In both cases, dynamic analysis is limited in functionality by complex debugging and instrumentation interfaces and in performance by low execution speeds on Microcontroller Units (MCUs) and Instruction Set Architecture (ISA) translation overheads in emulators. SURGEON provides a performant, flexible, and accurate rehosting approach for dynamic analysis of embedded firmware. We introduce transplantation to transform binary, embedded f irmware into a Linux user space process executing natively on compatible high-performance systems through static binary rewriting. In addition to the achieved performance improvements, SURGEON scales horizontally through process instantiation and provides the flexibility to apply existing dynamic analysis tooling for user space processes without requiring adaptations to firmware-specific use cases. SURGEON’s key use cases include debugging binary firmware with off-the-shelf tooling for user space processes and fuzz testing.