AMD Server Vulnerabilities – August 2024

Bulletin ID: AMD-SB-3003 **Potential Impact:**Varies by CVE, see descriptions below Severity: Varies by CVE, see descriptions below

Summary

Potential vulnerabilities in the AMD Secure Processor (ASP), AMD Secure Encrypted Virtualization (SEV), AMD Secure Encrypted Virtualization – Secure Nested Paging (SEV-SNP) and other platform components were discovered, and mitigations have been provided in AMD EPYC™ Platform Initialization (PI) firmware packages.

Please refer to your OEM for the BIOS update specific to your product.

CVE Details

Refer to Glossary for explanation of terms

CVE	CVSS Score	CVE Description
CVE-2023-20578	7.5 (High)AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H	A TOCTOU (Time-Of-Check-Time-Of-Use) in SMM may allow an attacker with ring0 privileges and access to the BIOS menu or UEFI shell to modify the communications buffer, potentially resulting in arbitrary code execution.
CVE-2021-26344	7.2 (High)AV:L/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:H	An out of bounds memory write when processing the AMD PSP1 Configuration Block (APCB) could allow an attacker with access the ability to modify the BIOS image, and the ability to sign the resulting image, to potentially modify the APCB block resulting in arbitrary code execution.
CVE-2023-20591	6.5 (Medium)AV:N /AC:H/PR:N/UI:N/S:C/ C:L/I:L/A:L	Improper re-initialization of IOMMU during the DRTM event may permit an untrusted platform configuration to persist, allowing an attacker to read or modify hypervisor memory, potentially resulting in loss of confidentiality, integrity, and availability.
CVE-2024-21981	5.7 (Medium)AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N	Improper key usage control in AMD Secure Processor (ASP) may allow an attacker with local access who has gained arbitrary code execution privilege in ASP to extract ASP cryptographic keys, potentially resulting in loss of confidentiality and integrity.
CVE-2023-20584	5.3 (Medium)AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N	IOMMU improperly handles certain special address ranges with invalid device table entries (DTEs), which may allow an attacker with privileges and a compromised Hypervisor (HV) to induce DTE faults to bypass RMP checks in SEV-SNP, potentially leading to a loss of guest integrity.
CVE-2021-46746	5.2 (Medium)AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H	Lack of stack protection exploit mechanisms in ASP Secure OS Trusted Execution Environment (TEE) may allow a privileged attacker with access to AMD signing keys to corrupt the return address, causing a stack-based buffer overrun, potentially leading to a denial of service.
CVE-2023-31356	4.4 (Medium)AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N	Incomplete system memory cleanup in SEV firmware could allow a privileged attacker to corrupt guest private memory, potentially resulting in a loss of data integrity.
CVE-2021-26387	3.9 (Low)AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:L	Insufficient access controls in ASP kernel may allow a privileged attacker with access to AMD signing keys and the BIOS menu or UEFI shell to map DRAM regions in protected areas, potentially leading to a loss of platform integrity.
CVE-2021-46772	3.9 (Low)AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:L	Insufficient input validation in the ABL may allow a privileged attacker with access to the BIOS menu or UEFI shell to tamper with the structure headers in SPI ROM causing an out of bounds memory read and write, potentially resulting in memory corruption or denial of service.
CVE-2023-20518	1.6 (Low)AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:N	Incomplete cleanup in the ASP may expose the Master Encryption Key (MEK) to a privileged attacker with access to the BIOS menu or UEFI shell and a memory exfiltration vulnerability, potentially resulting in loss of confidentiality.

Specific CVSS scores may change subject to your implementation. We encourage you to calculate CVSS scores independently for your system.

Mitigation

Refer to the Mitigation Options provided for each product below.

1st Gen AMD EPYC™ Processors formerly codenamed “Naples”

2nd Gen AMD EPYC™ Processors formerly codenamed “Rome”

3rd Gen AMD EPYC™ Processors formerly codenamed “Milan"

4th Gen AMD EPYC™ Processors formerly codenamed “Genoa"

1st Gen AMD EPYC™ Processors formerly codenamed “Naples”

AMD recommends updating to the Platform Initialization (PI) firmware version indicated below.
There are no other available mitigation options.

CPUIDs	Mitigation Option 1	Mitigation Option 2
0x00800F12	**Platform
Initialization (PI)****(Requires FW flash)**	μcode**(Hot loadable)**	SEV FW Minimum firmware versions to mitigate all applicable CVEs
CVE-2021-26344	(High)	No fix planned1
CVE-2023-20578	(High)	NaplesPI 1.0.0.K(2023-06-14)
CVE-2021-46746	(Medium)	No fix planned2
CVE-2023-20584	(Medium)	Not affected
CVE-2023-20591	(Medium)	Not affected
CVE-2023-31356	(Medium)	Not affected
CVE-2024-21981	(Medium)	No fix planned3
CVE-2021-26387	(Low)	No fix planned2
CVE-2021-46772	(Low)	Not affected
CVE-2023-20518	(Low)	Not affected

2nd Gen AMD EPYC™ Processors formerly codenamed “Rome”

AMD recommends updating to the Platform Initialization (PI) firmware version indicated below.
There are no other available mitigation options.

CPUIDs	Mitigation Option 1	Mitigation Option 2
0x00830F10h	PlatformInitialization (PI)(Requires FW flash)	μcode**(Hot loadable)**
CVE-2021-26344	(High)	RomePI 1.0.0.C(2021-07-22)
CVE-2023-20578	(High)	RomePI 1.0.0.G(2023-05-05)
CVE-2021-46746	(Medium)	No fix planned2
CVE-2023-20584	(Medium)	Not affected
CVE-2023-20591	(Medium)	Not affected
CVE-2023-31356	(Medium)	Not affected
CVE-2024-21981	(Medium)	No fix planned3
CVE-2021-26387	(Low)	No fix planned2
CVE-2021-46772	(Low)	RomePI 1.0.0.E(2022-06-17)
CVE-2023-20518	(Low)	Not affected

3rd Gen AMD EPYC™ Processors formerly codenamed “Milan"

AMD recommends updating to the Platform Initialization (PI) firmware version indicated below.
For some CVEs, there may be alternative mitigation options provided as Mitigation Option 2, including microcode and/or other patches.

CPUIDs	Mitigation Option 1	Mitigation Option 2	TCB ValuesforSNP Attestation****
0x00A00F110x00A00F12****	PlatformInitialization (PI)(Requires FW flash)	μcode**(Hot loadable)**	SEV FW**(Hot loadable)** Minimum firmware versions to mitigate all applicable CVEs below
CVE-2021-26344	(High)
MilanPI 1.0.0.5(2021-08-05)	N/A	N/A	N/A
CVE-2023-20578	(High)	MilanPI 1.0.0.B(2023-06-08)	N/A
CVE-2021-46746	(Medium)	No fix planned2	N/A
CVE-2023-20584	(Medium)	MilanPI 1.0.0.C(2023-12-18)	N/A
CVE-2023-20591	(Medium)	MilanPI 1.0.0.B(2023-06-08)	N/A
CVE-2023-31356	(Medium)	MilanPI 1.0.0.C(2023-12-18)	N/A
CVE-2024-21981	(Medium)	No fix planned3	N/A
CVE-2021-26387	(Low)	No fix planned2	N/A
CVE-2021-46772	(Low)	MilanPI 1.0.0.9(2022-05-21)	N/A
CVE-2023-20518	(Low)	Not affected	N/A

4th Gen AMD EPYC™ Processors formerly codenamed “Genoa”

AMD recommends updating to the Platform Initialization (PI) firmware version indicated below.
For some CVEs, there may be alternative mitigation options provided as Mitigation Option 2, including microcode and/or other patches.

CPUIDs|Mitigation Option 1|**Mitigation Option 2

|TCB Values forSNP Attestation**
—|—|—|—
0x00A10F110x00A10F120x00AA0F02****|PlatformInitialization (PI)(Requires FW flash)|μcode**(Hot loadable)|SEV FW**(Hot loadable) Minimum firmware versions to mitigate all listed CVEs| GenoaPI 1.0.0.B(2023-12-15)
CVE-2021-26344| (High)| Not affected| N/A| N/A| N/A
CVE-2023-20578| (High)| GenoaPI 1.0.0.2(2022-10-04)| N/A| N/A| N/A
CVE-2021-46746| (Medium)| No fix planned2| N/A| N/A| N/A
CVE-2023-20584| (Medium)| GenoaPI 1.0.0.B(2023-12-15)| N/A| SEV firmware 1.55.23[hex 1.37.17]|
TCB[SNP] >= 0xF
CVE-2023-20591| (Medium)| Genoa 1.0.0.8(2023-06-09)| N/A| N/A| N/A
CVE-2023-31356| (Medium)| GenoaPI 1.0.0.B(2023-12-15)| N/A| 1.55.31[hex 1.37.1F]| TCB[SNP] >= 0x13
CVE-2024-21981| (Medium)| Not affected| N/A| N/A| N/A
CVE-2021-26387| (Low)| No fix planned2| N/A| N/A| N/A
CVE-2021-46772| (Low)| Not affected| N/A| N/A| N/A
CVE-2023-20518| (Low)| GenoaPI 1.0.0.4(2022-12-22)| N/A| N/A| N/A