: Non-volatile storage (NVRAM) variables can sometimes be manipulated to bypass passwords or alter the Secure Boot policy. Tools like UEFI Tool and Universal-IFR-Extractor are used to reverse-engineer these modules and identify sensitive offsets.
: Open-source tools like CHIPSEC allow administrators to test their systems for known vulnerabilities, such as improperly protected S3 boot scripts or exposed SMI handlers. The Future: Open Source vs. Opaque Firmware Attacking and Defending BIOS
: SMM is a highly privileged execution mode used for low-level hardware control. Attackers target SMI (System Management Interrupt) handlers —specifically looking for "SMI input pointer" vulnerabilities—to extract protected data from SMRAM or overwrite firmware. : Non-volatile storage (NVRAM) variables can sometimes be
: Defenders use scripts and hardware registers (like the BIOS_CNTL register) to ensure BIOS hardware write-protection is enabled, preventing unauthorized flashing. The Future: Open Source vs
: Reducing the attack surface is critical. Platforms like DECAF perform "dynamic surgery" on UEFI binaries to remove unnecessary code without affecting performance, effectively hardening the firmware.
Defending the BIOS requires a multi-layered "Chain of Trust" that begins at the hardware level.