AMD Server Vulnerabilities – May 2023

Bulletin ID: AMD-SB-3001 **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 System Management Unit (SMU), AMD Secure Encrypted Virtualization (SEV) and other platform components were discovered, and mitigations have been provided in AMD EPYC™ AGESA™ PI packages.

Affected Products

AMD EPYC™ Servers

CVE Details

CVE	Severity	Description
CVE-2021-46769	High	Insufficient syscall input validation in the ASP Bootloader may allow a privileged attacker to execute arbitrary DMA copies, which can lead to code execution.
CVE-2021-26354	Medium	Insufficient bounds checking in ASP may allow an attacker to issue a system call from a compromised ABL which may cause arbitrary memory values to be initialized to zero, potentially leading to a loss of integrity.
CVE-2021-26356	Medium	A TOCTOU in ASP bootloader may allow an attacker to tamper with the SPI ROM following data read to memory potentially resulting in S3 data corruption and information disclosure.
CVE-2021-26371	Medium	A compromised or malicious ABL or UApp could send a SHA256 system call to the bootloader, which may result in exposure of ASP memory to userspace, potentially leading to information disclosure.
CVE-2021-26379	Medium	Insufficient input validation of mailbox data in the SMU may allow an attacker to coerce the SMU to corrupt SMRAM, potentially leading to a loss of integrity and privilege escalation.
CVE-2021-26397	Medium	Insufficient address validation, may allow an attacker with a compromised ABL and UApp to corrupt sensitive memory locations potentially resulting in a loss of integrity or availability.
CVE-2021-26406	Medium	Insufficient validation in parsing Owner’s Certificate Authority (OCA) certificates in SEV (AMD Secure Encrypted Virtualization) and SEV-ES user application can lead to a host crash potentially resulting in denial of service.
CVE-2021-46756	Medium	Insufficient validation of inputs in SVC_MAP_USER_STACK in the ASP (AMD Secure Processor) bootloader may allow an attacker with a malicious Uapp or ABL to send malformed or invalid syscall to the bootloader resulting in a potential denial of service and loss of integrity.
CVE-2021-46763	Medium	Insufficient input validation in the SMU may enable a privileged attacker to write beyond the intended bounds of a shared memory buffer potentially leading to a loss of integrity.
CVE-2021-46764	Medium	Improper validation of DRAM addresses in SMU may allow an attacker to overwrite sensitive memory locations within the ASP potentially resulting in a denial of service.
CVE-2021-46775	Medium	Improper input validation in ABL may enable an attacker with physical access, to perform arbitrary memory overwrites, potentially leading to a loss of integrity and code execution.
CVE-2022-23818	Medium	Insufficient input validation on the model specific register: VM_HSAVE_PA may potentially lead to loss of SEV-SNP guest memory integrity.
CVE-2021-46762	Medium	Insufficient input validation in the SMU may allow an attacker to corrupt SMU SRAM potentially leading to a loss of integrity or denial of service.
CVE-2023-20524	Medium	An attacker with a compromised ASP could possibly send malformed commands to an ASP on another CPU, resulting in an out of bounds write, potentially leading to a loss a loss of integrity.
CVE-2023-20520	Medium	Improper access control settings in ASP Bootloader may allow an attacker to corrupt the return address causing a stack-based buffer overrun potentially leading to arbitrary code execution.

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

Mitigation

The AGESA™ versions listed below have been released to the Original Equipment Manufacturers (OEM) to help mitigate these issues. Please refer to your OEM for the BIOS update specific to your product.

CVE|1st Gen AMD EPYC™ Processors|2nd Gen AMD EPYC™ Processors|3rd Gen AMD EPYC™
Processors|4th Gen AMD EPYC™
Processors
—|—|—|—|—
Minimum version to mitigate all listed CVEs|NaplesPI 1.0.0.J|RomePI 1.0.0.E
| MilanPI 1.0.0.9
|“Genoa”
(Product not impacted)
CVE-2021-26354| N/A| RomePI 1.0.0.C| MilanPI 1.0.0.4| N/A
CVE-2021-26356| NaplesPI 1.0.0.H| RomePI 1.0.0.D| MilanPI 1.0.0.6| N/A
CVE-2021-26371| NaplesPI 1.0.0.H| RomePI 1.0.0.D| MilanPI 1.0.0.6| N/A
CVE-2021-26379| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9| N/A
CVE-2021-26397| N/A| N/A| MilanPI 1.0.0.9| N/A
CVE-2021-26406| NaplesPI 1.0.0.E| RomePI 1.0.0.A| N/A| N/A
CVE-2021-46756| NaplesPI 1.0.0.J| RomePI 1.0.0.E| MilanPI 1.0.0.9

| N/A
CVE-2021-46762| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9| N/A
CVE-2021-46763| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9| N/A
CVE-2021-46764| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9| N/A
CVE-2021-46769| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9

| N/A
CVE-2021-46775| N/A| RomePI 1.0.0.E| MilanPI 1.0.0.9| N/A
CVE-2022-23818| N/A| N/A| MilanPI 1.0.0.9| N/A
CVE-2023-20520| NaplesPI 1.0.0.H| RomePI 1.0.0.D| MilanPI 1.0.0.5| N/A
CVE-2023-20524| N/A| RomePI 1.0.0.C| MilanPI 1.0.0.5| N/A

SEV TABLE

CVE ID|

SEV|

SEV-ES|

SEV-SNP
—|—|—|—
CVE-2021-26354| Y| Y| Y
CVE-2021-26356| N/A| N/A| N/A
CVE-2021-26371| N| N| Y
CVE-2021-26379| N| Y| Y
CVE-2021-26397| N| Y| Y
CVE-2021-26406| Y| Y| N
CVE-2021-46756| Y| Y| Y
CVE-2021-46763| N| N| Y
CVE-2021-46764| Y| Y| Y
CVE-2021-46769| Y| Y| Y
CVE-2021-46762| Y| Y| Y
CVE-2021-46775| Y| Y| Y
CVE-2022-23818| N| N| Y
CVE-2023-20520| N| N| N/A
CVE-2023-20524| N| N| N

SEV applicability:

Name|

SEV|

SEV-ES|

SEV-SNP
—|—|—|—
Naples| Applicable| Applicable| Not Applicable
Rome| Applicable| Applicable| Not Applicable
Milan| Applicable| Applicable| Applicable
Genoa| Applicable| Applicable| Applicable
Trento| Not Applicable|Not Applicable|Not Applicable