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Medium

AMD IOMMU RMP Check Bypass Leading to Guest Memory Integrity Corruption

IdentifiersCVE-2023-20585CWE-125

CVE-2023-20585 is an AMD IOMMU-related vulnerability caused by insufficient checks of the Reverse Map Table (RMP) during host buffer access. According to the provided content, the flaw allows an attacker with privileges and a compromised hypervisor to trigger an out-of-bounds condition without the expected RMP checks. The issue affects confidential computing guest protections and has been described by Microsoft as an AMD IOMMU Write Buffer vulnerability that could lead to corruption of guest encrypted memory. The Linux kernel fix references the iommu/amd subsystem and specifically notes a remediation to use the maximum event log buffer size when Secure Nested Paging (SNP) is enabled on AMD Family 0x19 systems.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can undermine confidential guest integrity by enabling corruption or tampering of guest encrypted memory or other protected guest state. The provided content does not indicate a direct confidentiality or availability impact, but it does explicitly state integrity loss for confidential guests and guest encrypted memory corruption as the primary consequence.

Mitigation

If you can’t patch tonight, do this now.

The provided content indicates that mitigation is primarily patch-based. Apply the relevant Windows update or updated Linux kernel packages from the platform vendor. Because exploitation requires a compromised hypervisor and high privileges, reducing exposure of confidential-computing workloads to untrusted or compromised hypervisors and limiting privileged access on the host may reduce risk, but specific non-patch mitigations are not provided in the source content.

Remediation

Patch, then assume compromise.

Apply vendor-provided updates that address CVE-2023-20585. In the Linux kernel context provided, SUSE remediated the issue in iommu/amd by using the maximum event log buffer size when SNP is enabled on Family 0x19, with fixed kernel package versions released across supported SUSE product lines. In the Microsoft context, install the latest supported Windows build or relevant Windows security update, which Microsoft states enables the mitigation for this vulnerability. Where applicable, consult AMD bulletin AMD-SB-3016 and platform vendor advisories for product-specific fixed versions.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

10 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

10 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2023-20585
NVD
nvd.nist.gov/vuln/detail/CVE-2023-20585
MITRE CWE · CWE-125
cwe.mitre.org
amd.com
amd.com/en/resources/product-security/bulletin/AMD-SB-3016.html