Intel Boot Guard and Intel TXT (hardware debug / INIT): Hardware debug modes and processor INIT handling can override

Impact

Hardware debug modes and processor INIT handling can override the locks that Boot Guard and TXT rely on, letting an unauthenticated attacker escalate privilege and defeat measured/verified boot. This reaches both of Intel's boot-integrity technologies at once - the two things a remote attestation claim about a bare-metal node ultimately rests on.

Who can reach it

An attacker with the ability to trigger the relevant debug or INIT conditions - realistically physical or deep platform access.

What to do

Platform BIOS/firmware update from the OEM. Drain and reboot per node, and wait on OEM packaging. Until then, treat Boot Guard and TXT measurements from affected platforms as advisory rather than authoritative in any attestation policy you enforce.

References