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Windows NTLM Elevation of Privilege Vulnerability

IdentifiersCVE-2025-54918CWE-287· Improper Authentication

CVE-2025-54918 is an elevation-of-privilege vulnerability in Windows NTLM caused by improper authentication. The available reporting indicates that an authorized/authenticated attacker can send specially crafted network traffic to a target system and exploit flaws in NTLM authentication handling to elevate privileges over the network, ultimately obtaining SYSTEM privileges on the affected host. Multiple sources in the provided content characterize the issue as affecting Windows NTLM authentication across supported Windows client and server platforms. Some reporting further claims the flaw may enable bypass of protections such as LDAP signing and channel binding in NTLM relay-to-LDAP scenarios, but the precise technical mechanism is not confirmed in the provided material.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

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

Successful exploitation allows an authenticated attacker to escalate privileges from an existing authorized position to SYSTEM on the target system over the network. In enterprise Windows environments, this can materially increase post-compromise impact by enabling local full control of affected hosts, facilitating lateral movement, persistence, credential access, and potentially broader Active Directory compromise when chained with relay or directory-service abuse techniques.

Mitigation

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

Until patching is fully deployed, reduce exposure to NTLM-based attack paths where operationally feasible. The provided content indicates stronger defensive measures include reducing or disabling NTLM in favor of Kerberos-only operation where possible, enforcing LDAP channel binding, and maintaining related authentication hardening controls. Because some reporting suggests this issue may undermine assumptions about LDAP signing/channel binding in certain relay scenarios, these measures should be treated as defense-in-depth rather than a substitute for patching.

Remediation

Patch, then assume compromise.

Apply Microsoft's September 2025 security updates for CVE-2025-54918 to all affected Windows systems, including supported workstation and server versions referenced in the provided content. Because the issue is in Windows NTLM authentication, remediation should focus on timely deployment of the vendor patch across the estate and verification of patch compliance on domain-joined systems and servers exposed to NTLM-based authentication flows.
PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.

VALID 0 / 2 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Microsoft CorporationWindows 10 1507operating_system
Microsoft CorporationWindows 10 1607operating_system
Microsoft CorporationWindows 10 1809operating_system
Microsoft CorporationWindows 10 21h2operating_system
Microsoft CorporationWindows 10 22h2operating_system
Microsoft CorporationWindows 11 22h2operating_system
Microsoft CorporationWindows 11 23h2operating_system
Microsoft CorporationWindows 11 24h2operating_system
Microsoft CorporationWindows Server 2008operating_system
Microsoft CorporationWindows Server 2008 R2operating_system
Microsoft CorporationWindows Server 2008 Sp2operating_system
Microsoft CorporationWindows Server 2012operating_system
Microsoft CorporationWindows Server 2012 R2operating_system
Microsoft CorporationWindows Server 2016operating_system
Microsoft CorporationWindows Server 2019operating_system
Microsoft CorporationWindows Server 2022operating_system
Microsoft CorporationWindows Server 2022 23h2operating_system
Microsoft CorporationWindows Server 2025operating_system
Microsoft CorporationWindows Server 23h2operating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures1

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

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

Social activity55

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