#VU97952 Improper access control in AMD products - CVE-2021-26387

Vulnerability identifier: #VU97952

Vulnerability risk: Low

CVSSv4.0: 0.2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-26387

CWE-ID: CWE-284

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
1st Gen AMD EPYC Processors
Hardware solutions / Firmware
2nd Gen AMD EPYC Processors
Hardware solutions / Firmware
3rd Gen AMD EPYC Processors
Hardware solutions / Firmware
4th Gen AMD EPYC Processors
Hardware solutions / Firmware

Vendor: AMD

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to improper access restrictions in ASP kernel. A local privileged user with access to AMD signing keys and the BIOS menu or UEFI shell can map DRAM regions in protected areas.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

The vendor is not planning to release security fixes to address this vulnerability.

Vulnerable software versions

1st Gen AMD EPYC Processors: All versions

2nd Gen AMD EPYC Processors: All versions

3rd Gen AMD EPYC Processors: All versions

4th Gen AMD EPYC Processors: All versions

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External links
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3003.html
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-5002.html

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.