In Lenovo systems, SMM BIOS Write Protection is used to prevent writes to SPI Flash. While this provides sufficient protection, an additional layer of protection is provided by SPI Protected Range Registers (PRx). Lenovo was notified that after resuming from S3 sleep mode in various versions of BIOS for Lenovo systems, the PRx is not set. This does not impact the SMM BIOS Write Protection, which keeps systems protected.
A vulnerability has been identified in some Lenovo products that use UEFI (BIOS) code developed by American Megatrends, Inc. (AMI). With this vulnerability, conditions exist where an attacker with administrative privileges or physical access to a system may be able to run specially crafted code that can allow them to bypass system protections such as Device Guard and Hyper-V.
The BIOS for Lenovo ThinkCentre E93, M6500t/s, M6600, M6600q, M6600t/s, M73p, M800, M83, M8500t/s, M8600t/s, M900, M93, and M93P devices; ThinkServer RQ940, RS140, TS140, TS240, TS440, and TS540 devices; and ThinkStation E32, P300, and P310 devices might allow local users or physically proximate attackers to bypass the Secure Boot protection mechanism by leveraging an AMI test key.