AMD Secure Processor (ASP) kernel: Improper parameter handling in the ASP's own kernel gives a privileged attacker

Impact

Improper parameter handling in the ASP's own kernel gives a privileged attacker a path to elevate inside the secure processor and damage platform integrity. Same practical outcome as the ASP driver flaw: root on the box becomes control of the firmware trust anchor.

Who can reach it

Local, privileged.

What to do

Fixed in AMD reference firmware (AGESA / SEV firmware) and delivered to you only as an OEM SBIOS/BIOS package - Dell, HPE, Supermicro, Lenovo, Gigabyte and the ODMs each rebuild and requalify AMD's AGESA drop before it ships. **Expect months, not weeks**: AMD publishes the bulletin, the OEM ships BIOS somewhere between one and six months later, and for platforms past their support window it may never arrive at all. Applying it is a full node power cycle with the host drained - not a driver reload, not a live patch. Track it as a firmware campaign per server SKU, not per kernel version, and verify afterwards by reading back the SMU/PSP firmware version rather than trusting the BIOS revision string.

References