AMD Platform Security Processor

[1] According to an AMD developer's guide, the subsystem is "responsible for creating, monitoring and maintaining the security environment" and "its functions include managing the boot process, initializing various security related mechanisms, and monitoring the system for any suspicious activity or events and implementing an appropriate response".

In 2019, a Berlin-based security group discovered the off-chip firmware in ordinary UEFI image files (the code that boots up the operating system), which meant that it could be easily analyzed.

By using a few hand-written Python-based tools, they found that the off-chip firmware from the SPI ROM contained an application resembling an entire micro operating system.

They discovered that the firmware is run inside in the same system's memory space that user's applications do with unrestricted access to it (including MMIO) raising concerns over data safety.

In September 2017, Google security researcher Cfir Cohen reported a vulnerability to AMD of a PSP subsystem that could allow an attacker access to passwords, certificates, and other sensitive information; a patch was rumored to become available to vendors in December 2017.