AMD Secure Processor (ASP) firmware system-call interface: MULTI-TENANT ISOLATION: The ASP firmware does not validate

Impact

MULTI-TENANT ISOLATION: The ASP firmware does not validate addresses passed across its system-call boundary, so a compromised user application that can issue ASP syscalls can steer the secure processor into reading or writing memory of the caller's choosing, ending in code execution inside the ASP. That converts a userspace compromise into control of the platform's security engine.

Who can reach it

Local. Requires an already-compromised application with ASP syscall access - typically a privileged agent or a trusted application, not a plain tenant container.

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