CVE-2025-21374
📋 TL;DR
This vulnerability in the Windows Client Side Caching (CSC) service allows an authenticated attacker to read sensitive information from system memory. It affects Windows systems with the CSC service enabled, potentially exposing credentials or other sensitive data to local users.
💻 Affected Systems
- Windows Client Side Caching (CSC) service
📦 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 authenticated attacker could read sensitive information like credentials, encryption keys, or other privileged data from system memory, leading to privilege escalation or lateral movement.
Likely Case
Local authenticated users could read limited sensitive information from memory, potentially exposing some system data but not full system compromise.
If Mitigated
With proper access controls and monitoring, impact is limited to information disclosure within the attacker's existing privilege level.
🎯 Exploit Status
Requires local authenticated access. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21374
Restart Required: Yes
Instructions:
1. Apply the latest Windows security updates from Microsoft. 2. Restart the system to complete the installation. 3. Verify the update was successfully applied.
🔧 Temporary Workarounds
Disable CSC Service
windowsDisables the Client Side Caching service to prevent exploitation
sc config csc start= disabled
sc stop csc
🧯 If You Can't Patch
- Restrict local user access to systems with CSC service enabled
- Implement strict access controls and monitoring for authenticated user activities
🔍 How to Verify
Check if Vulnerable:
Check if CSC service is running: sc query cscCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history shows the relevant security update installed📡 Detection & Monitoring
Log Indicators:
- Unusual CSC service activity
- Multiple failed CSC service access attempts
- Unexpected memory read operations
Network Indicators:
- Local system calls to CSC service with unusual patterns
SIEM Query:
EventID=4688 AND ProcessName LIKE '%csc%' AND CommandLine CONTAINS 'memory'