AMD is reportedly determined but has not yet released updates to the general public for one security error which affects the AMD Secure processor.
This component, formerly known as AMD PSP (Platform Security Processor), it is one chip-on-chip security system, similar to its Management Engine (ME) Intel.
Just like Intel ME processors, AMD Secure Processors are a complete collaborative Processor which sits alongside the actual AMD64 x86 CPU cores and has a separate processing system that is tasked with handling various security-related functions.
Cfir Cohen, a security researcher with the Google Cloud Security team, reports that he discovered a vulnerability in the AMD Secure Processor Trusted Platform Module (TPM).
TPM is a component for storing critical system data, such as passwords, certificates, and encryption keys, and is located in a "secure" environment and outside of AMD's most easily accessible cores.
"Through static analysis, we found a stack overflow in the EkCheckCurrentCert function," reports Cohen. The researcher claims that an attacker could use specially configured certificates (EK certificates) to gain remote privileges implementationof code to the AMD Secure processor, effectively breaking the security it offers.
Cohen mentioned that some basic mitigation techniques, such as stack cookies, NX stack, and ASLR. To date, however, they have not been implemented in AMD's Secure Processor, making exploit very easy.
Intel Me ™ processors use a similar TPM, but Cohen does not say whether it is affected.
Google researcher reported defect to AMD in September and AMD told researcher in December that it has developed an update and is preparing for its release.
Coincidentally, in Reddit [1, 2], some have reported seeing a new option that allows AMD PSP to be disabled, but it is unclear whether this new option is related to the updates that AMD reports on Cohen's findings.
Let's say a PSP disable option is somewhat unique in the CPU world. For example, Intel has never allowed users to disable its secret partner despite the long list of security flaws reported for that particular item.
Cohen's revelation of the AMD Secure Processor processor flaw came the same day that Google researchers revealed the details of the Meltdown and Specter defects that affect most of the world's CPUs.
Last November, Intel again provided updates for several similar weaknesses in Intel ME which allowed attackers to install rootkits and retrieve data from the safe parts of Intel processors.
