CVE-2024-43451 Microsoft CVE debrief

Who should care

Windows administrators, endpoint and server security teams, identity/authentication owners, and incident responders responsible for Microsoft Windows systems that use NTLM/NTLMv2.

Technical summary

The supplied sources identify CVE-2024-43451 as a Microsoft Windows NTLMv2 hash disclosure spoofing vulnerability. CISA classifies it as known exploited, so defenders should treat it as a live exposure rather than a theoretical issue. The available corpus does not provide CVSS scoring or detailed exploit mechanics, so remediation should follow Microsoft guidance and KEV prioritization.

Defensive priority

Urgent

Recommended defensive actions

• Apply Microsoft security updates or mitigations for CVE-2024-43451 as directed by vendor guidance.
• Prioritize all exposed Windows endpoints and servers in your remediation plan before the CISA due date of 2024-12-03.
• If mitigations are not available for a system, follow CISA guidance to discontinue use of the product or service until it can be secured.
• Review authentication-related telemetry and endpoint alerts for signs of abnormal NTLM activity.
• Confirm remediation across the full Windows estate, including laptops, servers, and identity-adjacent infrastructure.

Evidence notes

CISA’s Known Exploited Vulnerabilities catalog lists this item as "Microsoft Windows NTLMv2 Hash Disclosure Spoofing Vulnerability" with dateAdded 2024-11-12 and dueDate 2024-12-03. The KEV metadata states "knownRansomwareCampaignUse: Unknown" and directs operators to apply mitigations per vendor instructions or discontinue use if mitigations are unavailable. The supplied source-item notes reference Microsoft’s MSRC update guide and the NVD detail page. The supplied CVE timeline fields show publishedAt and modifiedAt as 2024-11-12.

Official resources