#VU84026 Time-of-check Time-of-use (TOCTOU) Race Condition in AMD products - CVE-2023-20521

Vulnerability identifier: #VU84026

Vulnerability risk: Low

CVSSv4.0: 0.4 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2023-20521

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 an attacker to perform a denial of service attack.

The vulnerability exists due to a race condition in ASP Bootloader. An attacker with physical access to device can tamper with SPI ROM records after memory content verification and gain access to sensitive information of perform a denial of service (DoS) attack.

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 1.0.0.7

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External links
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3002.html

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Q & A

Can this vulnerability be exploited remotely?

No. The attacker should have physical access to the system in order to successfully exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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