System x Secure Boot Vulnerability
Lenovo Security Advisory: LEN-20241
Potential Impact: Booting unauthenticated code
Severity: High
Scope of Impact: Lenovo-only
CVE Identifier: CVE-2017-3775
Lenovo internal testing discovered some System x server BIOS/UEFI versions that, when Secure Boot mode is enabled by a system administrator, do not properly authenticate signed code before booting it. As a result, an attacker with physical access to the system could boot unsigned code. Lenovo ships these systems with Secure Boot disabled by default, because signed code is relatively new in the data center environment, and standard operator configurations disable signature checking. Apply the BIOS/UEFI update appropriate for your model described in the product impact section below. If you are relying on Secure Boot, you may want to control physical access to systems prior to applying the updates.[…]
https://support.lenovo.com/us/en/solutions/len-20241
https://threatpost.com/lenovo-patches-arbitrary-code-execution-flaw/131725/
Firmware Security 