#VU75925 Time-of-check Time-of-use (TOCTOU) Race Condition in AMD products - CVE-2021-26356

Vulnerability identifier: #VU75925

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-26356

CWE-ID: CWE-367

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

Vendor: AMD

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to a race condition in ASP bootloader. A local user can tamper with the SPI ROM, corrupt S3 data and gain access to sensitive information.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

1st Gen AMD EPYC Processors: before NaplesPI 1.0.0.H

2nd Gen AMD EPYC Processors: before RomePI 1.0.0.D

3rd Gen AMD EPYC Processors: before MilanPI 1.0.0.6

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External links
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3001.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.