CVE-2025-47979
📋 TL;DR
This vulnerability allows sensitive information to be written to log files in Windows Failover Cluster. An authenticated attacker with local access could read these logs to obtain confidential data. This affects organizations using Windows Failover Clustering for high availability services.
💻 Affected Systems
- Windows Server Failover Cluster
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An attacker with local access could extract sensitive credentials or configuration data from logs, potentially enabling lateral movement or privilege escalation within the cluster environment.
Likely Case
An authorized user with malicious intent could access sensitive cluster configuration details or credentials stored in log files, compromising cluster security.
If Mitigated
With proper access controls and log file permissions, the risk is limited to authorized administrators who already have elevated access to the system.
🎯 Exploit Status
Requires local access and authorized permissions to access log files. Exploitation involves reading log files that contain sensitive information.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: To be determined from Microsoft's monthly security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-47979
Restart Required: No
Instructions:
1. Apply the latest Windows Server security updates from Microsoft. 2. Verify the update is installed via Windows Update or WSUS. 3. No cluster restart required, but monitor cluster health after update.
🔧 Temporary Workarounds
Restrict log file access
WindowsModify NTFS permissions on Failover Cluster log directories to restrict access to authorized administrators only.
icacls "C:\Windows\Cluster\Logs" /inheritance:r /grant "Administrators:(OI)(CI)F" /grant "SYSTEM:(OI)(CI)F"
Enable log file encryption
WindowsConfigure Windows to encrypt log files using EFS (Encrypting File System) for sensitive log directories.
cipher /e "C:\Windows\Cluster\Logs"
🧯 If You Can't Patch
- Implement strict access controls on cluster nodes, limiting local log access to essential administrators only.
- Regularly audit and monitor access to cluster log files and implement alerting for unauthorized access attempts.
🔍 How to Verify
Check if Vulnerable:
Check if Windows Failover Clustering is enabled and review log file permissions in cluster directories.Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history for the relevant security patch and confirm log files no longer contain sensitive information in plain text.📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to cluster log directories
- Sensitive strings (passwords, credentials) appearing in log files
Network Indicators:
- N/A - This is a local information disclosure vulnerability
SIEM Query:
EventID=4663 AND ObjectName LIKE "%Cluster\Logs%" AND AccessMask=0x1