Processor vulnerability
CVE-2020-12890
Pointer handling in AGESA's SMM code let an attacker with physical or administrative access run code in SMM, hidden from the operating system.
- Name
- SMM callout in AGESA
- Vulnerability
- AMD AGESA, SMM and BIOS firmware
- Kind
- Firmware
- CVE published
- 2021-12-10 CVE record
AGESA is the firmware AMD gives board makers to start its
processors, and part of it runs in System Management Mode. Danny
Odler showed that its SMM code handled pointers it was given without
enough care, so that an attacker with administrative or physical
access could make SMM call code of the attacker’s choosing; code
running in SMM is out of the operating system’s sight. This is AMD’s
earliest SMM CVE and predates its numbered bulletins; AMD’s 2020
statement limits it to some client and embedded APUs launched from
2016 to 2019 and names no models.What the sources say of each microarchitecture.
Affected processors
2 of the 2 microarchitectures listed are affected in all or some of their models.
Mitigations
- Firmware: Updated AGESA versions, delivered to board makers by the end of June 2020, in BIOS updates. Source.
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