new AMD bugs/vulnr

[Edzo Botjes (edzob)]

https://www.tomshardware.com/news/amd-discloses-31-new-cpu-vulnerabilities

AMD has also listed 28 vulnerabilities for its EPYC processors, four of which are high severity. Three of the high-severity variants enable arbitrary code execution through various attack vectors, while one allows writing data to certain regions that can lead to loss of data integrity and availability. Researchers also unearthed 15 other vulnerabilities ranked as medium severity and nine low-severity vulnerabilities.

AMD's chips have long been known for having fewer known vulnerabilities than Intel's models. However, it's hard to ascertain if the initially limited discoveries in AMD processors were due to a security-first approach to hardened processor design, or if researchers and attackers merely focused on Intel's processors due to their commanding market share: Attackers almost always focus on the broadest cross-section possible.

As such, AMD's recent success in clawing away market share from Intel, especially in the security-focused data center market, will find researchers turning their eyes more toward AMD's architectures in search of potential security gaps. AMD has also had several other new vulnerability disclosures in the recent past, including a Meltdown-esque variant that requires software re-coding, along with Hertzbleed and Take A Way.

https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1032

CVE	Severity	CVE Description
CVE‑2021‑26316	High	Failure to validate the communication buffer and communication service in the BIOS may allow an attacker to tamper with the buffer resulting in potential SMM arbitrary code execution.
CVE-2021-26398	High	Insufficient input validation in SYS_KEY_DERIVE system call in a compromised user application or ABL may allow an attacker to corrupt ASP (AMD Secure Processor) OS memory which may lead to potential arbitrary code execution.
CVE-2021-26402	High	Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox commands, may allow an attacker to write partially-controlled data out-of-bounds to SMM or SEV-ES regions which may lead to a potential loss of integrity and availability.
CVE-2021-39298	High	A potential vulnerability in AMD System Management Mode (SMM) interrupt handler may allow an attacker with high privileges to access the SMM resulting in arbitrary code execution which could be used by malicious actors to bypass security mechanisms provided in the UEFI firmware.