VU#718077: UEFI Shell module embedded in SPI Flash can be used to bypass Secure Boot
Brief
Overview
The UEFI Shell program may expose raw memory access capabilities that, if present in platform firmware for debugging or advanced support use cases, could be abused to undermine UEFI Secure Boot protections.
When the UEFI Shell is included in SPI flash, an attacker with the ability to modify UEFI boot configuration may be able to create multiple boot option entries and bypass controls intended to prevent the UEFI Shell from launching while Secure Boot is enabled. This could allow an attacker to modify the pre-boot environment and execute unauthorized software during system startup.
Description
The Unified Extensible Firmware Interface (UEFI) is a firmware specification that defines the interface between a computing platform's hardware and operating system (OS) during the early boot process before the operating system is loaded.