AMD Secure Processor boot ROM - physical attacks bypassing secure boot: MULTI-TENANT ISOLATION: Physical attacks

Impact

MULTI-TENANT ISOLATION: Physical attacks that bypass secure boot in the ASP boot ROM. Boot ROM is mask-programmed silicon, so the flawed logic itself cannot be patched - only worked around by the firmware layered above it. An attacker who defeats ASP secure boot owns the platform's root of trust from power-on.

Who can reach it

Physical access to the platform.

What to do

**Boot ROM is unpatchable by construction** - any mitigation is compensating logic in AGESA/PI firmware above it, delivered as an OEM BIOS package. The real controls are physical: chain of custody for hardware, tamper evidence, and treating any node returned from third-party hands as untrusted until its firmware is measured and reprovisioned. This is the argument for firmware attestation between bare-metal tenants rather than trusting a reimage.

References