Improper Signature VerificationWeakness · CWE-347

CVE-2024-56161

HIGH · 7.2 CVSS v3.1 Published 2025-02-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Improper signature verification in AMD CPU ROM microcode patch loader may allow an attacker with local administrator privilege to load malicious CPU microcode resulting in loss of confidentiality and integrity of a confidential guest running under AMD SEV-SNP.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Improper signature verification in the AMD CPU ROM microcode patch loader allows a local administrator to load malicious CPU microcode, potentially compromising confidential guests running under AMD SEV-SNP by breaking confidentiality and integrity guarantees.

MitigationApply AMD-provided microcode/BIOS firmware updates when available, and strictly limit local administrator access to trusted personnel to reduce exploitation risk.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify CPU vendor
    Run 'lscpu' or check system information to confirm the processor is AMD-based
    Affected if System uses a non-AMD processor - the vulnerability only applies to AMD CPUs
  2. Verify SEV-SNP is enabled
    Check BIOS/UEFI settings or query SEV-SNP status via 'cat /sys/kernel/debug/sev/status' (Linux) or relevant hypervisor commands
    Affected if SEV-SNP is actively enabled and running confidential VMs - the flaw compromises SEV-SNP confidentiality/integrity guarantees
  3. Check current microcode version
    Query the loaded microcode version using 'dmesg | grep microcode' or 'cat /proc/cpuinfo' on Linux, or check BIOS/firmware version on Windows
    Affected if Microcode version is older than AMD-provided patches addressing signature verification flaws
  4. Review local administrator access
    Audit local administrator or root account access, review privileged user lists, and check for unauthorized accounts with administrative rights
    Affected if Untrusted or unauthorized local administrators exist - exploitation requires local administrator privileges to load malicious microcode
  5. Confirm hypervisor support for SEV-SNP
    Check hypervisor (e.g., QEMU/KVM, Hyper-V) version and SEV-SNP capability status via hypervisor documentation or 'virsh capabilities' output
    Affected if Hypervisor supports SEV-SNP but lacks updated microcode validation - vulnerable to loading improperly signed microcode

A system is affected if it runs on AMD CPU hardware with SEV-SNP enabled and has microcode versions prior to AMD's signature verification fix, combined with any untrusted local administrator access.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply AMD-provided microcode/BIOS firmware updates when available, and strictly limit local administrator access to trusted personnel to reduce exploitation risk.

Have this fixed Scoped from the published advisory
  • Consultation12.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
48.0 hours of engineering $8,520
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-56161 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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