Improper access control in AMD EPYC Processors

1) Improper access control

EUVDB-ID: #VU97952

Risk: Low

CVSSv3.1: 3.6 [CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:L/E:U/RL:U/RC:C]

CVE-ID: CVE-2021-26387

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

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

CPE2.3

• cpe:2.3:h:amd:1st_gen_amd_epyc_processors:*:*:*:*:*:*:*:*...
• cpe:2.3:h:amd:2nd_gen_amd_epyc_processors:*:*:*:*:*:*:*:*...
• cpe:2.3:h:amd:3rd_gen_amd_epyc_processors:*:*:*:*:*:*:*:*...
• cpe:2.3:h:amd:4th_gen_amd_epyc_processors:*:*:*:*:*:*:*:*...

External links

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

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.