X-Ray for Your BIOS: Carnegie Mellon’s New Open-Source Tool Pulls Back the Curtain on UEFI

Deciphering BIOS and UEFI updates is an endeavor typically conducted in obscurity. These files comprise a labyrinthine confluence of firmware, drivers, containers, images, and executable modules, yet few instruments exist that provide a coherent architectural perspective of their contents. Addressing this deficit, the CERT team from Carnegie Mellon SEI has introduced the CERT UEFI Parser, a Python-based utility engineered for the meticulous inspection of ROM firmware images, installers, and various UEFI-related artifacts.

The CERT UEFI Parser, developed for Python 3, leverages the Construct framework to delineate complex binary structures. Its architects assert that the parser offers superior flexibility compared to the EDK2 reference implementation, facilitating easier extension for proprietary or experimental formats. The project’s ultimate objective is the comprehensive interpretation of all data types residing within a UEFI ROM, encompassing PE files and diverse image structures.

The instrument is informed not only by formal UEFI specifications but also by the findings of independent firmware research—exemplified by Igor Skochinsky’s profound analyses of Intel ME. Crucially, the authors clarify that the project is unencumbered by Non-Disclosure Agreements (NDAs); all proprietary formats were reconstructed through open-source intelligence and original forensic analysis.

Operationalizing the parser requires the cert-uefi-support package, a suite of low-level utilities dedicated to binary unpacking and manipulation. Both packages are hosted on PyPI for installation within virtual environments. While a graphical user interface is available via PySide6, it remains an optional component to circumvent the substantial overhead of its dependencies.

The CERT UEFI Parser offers four distinct operational modalities: a GUI, a terminal-based text output with ANSI colorization, a comprehensive JSON export, and a streamlined “lite” JSON format optimized for the generation of Software Bill of Materials (SBOM). The developers recommend utilizing BIOS or UEFI updates sourced directly from hardware manufacturers as test specimens. While universal compatibility across all hardware models is not guaranteed, a vast array of prevalent vendor formats is already supported, and scrutinizing these updates provides an immediate testament to the tool’s analytical prowess.