CVE-2025-54918
📋 TL;DR
This vulnerability allows an authenticated attacker to exploit improper authentication in Windows NTLM to elevate privileges over a network. It affects Windows systems using NTLM authentication, potentially enabling attackers to gain higher privileges than intended.
💻 Affected Systems
- Windows NTLM authentication component
📦 What is this software?
Windows 10 1507 by Microsoft
Windows 10 1507 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1607 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 1809 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
An attacker gains domain administrator privileges, leading to complete network compromise, data exfiltration, ransomware deployment, or persistent backdoor installation.
Likely Case
Attackers with initial access escalate privileges to access sensitive systems, move laterally across the network, and compromise additional accounts.
If Mitigated
With proper network segmentation, privileged access management, and monitoring, impact is limited to isolated segments with minimal data exposure.
🎯 Exploit Status
Requires authenticated access and network connectivity to target; exploitation details not publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be specified in Microsoft Security Update
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-54918
Restart Required: Yes
Instructions:
1. Check Microsoft Security Update for patch details. 2. Apply Windows Update via Settings > Update & Security > Windows Update. 3. For enterprise: Deploy via WSUS, SCCM, or Intune. 4. Restart systems as required.
🔧 Temporary Workarounds
Disable NTLM authentication
windowsConfigure systems to use Kerberos only where possible
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "RestrictNTLM" -Value 1
Implement network segmentation
allRestrict NTLM traffic between network segments
🧯 If You Can't Patch
- Implement strict network segmentation to isolate systems using NTLM
- Enforce multi-factor authentication and privileged access management
🔍 How to Verify
Check if Vulnerable:
Check Windows version and NTLM configuration; monitor for Microsoft's specific detection guidanceCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history shows the relevant security patch installed📡 Detection & Monitoring
Log Indicators:
- Unusual NTLM authentication events
- Failed authentication followed by successful privileged access
- Event ID 4624 with NTLM logon type
Network Indicators:
- Anomalous NTLM traffic patterns
- Unexpected NTLM authentication from unusual sources
SIEM Query:
source="windows_security" event_id=4624 authentication_package="NTLM" | stats count by user, src_ip