CVE-2025-21257
📋 TL;DR
This vulnerability in Windows WLAN AutoConfig Service allows an authenticated attacker to read sensitive information from system memory. It affects Windows systems with WLAN functionality enabled. The vulnerability could expose network credentials or configuration data.
💻 Affected Systems
- Windows WLAN AutoConfig Service
📦 What is this software?
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 could extract WLAN credentials, network configuration data, or other sensitive information from memory, potentially enabling further network attacks.
Likely Case
Information disclosure of WLAN configuration details or temporary network credentials, which could aid in network reconnaissance or targeted attacks.
If Mitigated
Limited information exposure with minimal impact if proper network segmentation and access controls are implemented.
🎯 Exploit Status
Requires authenticated access to the target system. Exploitation involves specific API calls to trigger the memory read vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security Update KB5034441 (January 2025) or later
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21257
Restart Required: Yes
Instructions:
1. Open Windows Update settings. 2. Check for updates. 3. Install the January 2025 security updates. 4. Restart the system when prompted.
🔧 Temporary Workarounds
Disable WLAN AutoConfig Service
windowsDisables the vulnerable service if wireless functionality is not required
sc config WlanSvc start= disabled
sc stop WlanSvc
Restrict Service Permissions
windowsLimit which users can interact with the WLAN service
sc sdset WlanSvc D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)
🧯 If You Can't Patch
- Implement network segmentation to isolate wireless networks from critical systems
- Apply principle of least privilege to user accounts and monitor for unusual WLAN service access
🔍 How to Verify
Check if Vulnerable:
Check Windows version and installed updates. Systems without January 2025 security updates are vulnerable if WLAN service is running.Check Version:
wmic qfe list | findstr KB5034441Verify Fix Applied:
Verify KB5034441 or later security update is installed and WLAN service is running version 10.0.xxxxx.xxxx or higher.📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 with process name 'svchost.exe' and service name 'WlanSvc' showing unusual memory access patterns
- Increased WLAN service API calls from non-standard accounts
Network Indicators:
- Unusual WLAN configuration queries from internal systems
- Multiple authentication attempts to WLAN service from single source
SIEM Query:
source="Windows Security" AND (event_id=4688 OR event_id=4663) AND process_name="svchost.exe" AND service_name="WlanSvc"