CVE-2023-31355 — Improper restriction of write operations in SNP firmware could allow a malicious

Improper restriction of write operations in SNP firmware could allow a malicious hypervisor to overwrite a guest's UMC seed potentially allowing reading of memory from a decommissioned guest.

01What is this vulnerability?

Improper restriction of write operations in SNP firmware could allow a malicious hypervisor to overwrite a guest's UMC seed potentially allowing reading of memory from a decommissioned guest.

02Affected products

Vendor	Product	Versions
AMD	3rd Gen AMD EPYC™ Processors	various
AMD	4th Gen AMD EPYC™ Processors	various
AMD	AMD EPYC™ Embedded 7003	various
AMD	AMD EPYC™ Embedded 9003	various

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2024-08-05T16:04:24.813Z
• Last modified: 2024-08-06T14:58:40.899Z

09References

• https: — https://https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3011.h…