CVE-2025-49762
📋 TL;DR
A race condition vulnerability in Windows Ancillary Function Driver for WinSock allows authenticated attackers to escalate privileges locally. This affects Windows systems with the vulnerable driver component. Attackers must already have some level of access to exploit this vulnerability.
💻 Affected Systems
- Windows Ancillary Function Driver for WinSock (afd.sys)
📦 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
Complete system compromise with SYSTEM-level privileges, enabling installation of persistent malware, credential theft, and lateral movement across the network.
Likely Case
Local privilege escalation from standard user to administrator/SYSTEM privileges, allowing attackers to bypass security controls and execute arbitrary code.
If Mitigated
Limited impact if proper privilege separation and least privilege principles are enforced, though successful exploitation still provides elevated access.
🎯 Exploit Status
Race condition exploitation requires precise timing and understanding of the driver's internal state. Requires authenticated access to the system.
🛠️ 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-2025-49762
Restart Required: Yes
Instructions:
1. Apply latest Windows security updates from Microsoft. 2. Install the specific KB patch mentioned in the advisory. 3. Restart the system to complete the update.
🔧 Temporary Workarounds
Restrict user privileges
windowsImplement least privilege principle to limit impact if exploited
Monitor for suspicious activity
windowsEnable detailed logging and monitor for privilege escalation attempts
🧯 If You Can't Patch
- Implement strict access controls and limit user privileges to reduce attack surface
- Deploy endpoint detection and response (EDR) solutions to detect privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for the specific KB patch mentioned in Microsoft advisoryCheck Version:
wmic qfe list | findstr KB[number] or systeminfo | findstr HotfixVerify Fix Applied:
Verify the patch is installed via Windows Update or by checking system version against patched versions📡 Detection & Monitoring
Log Indicators:
- Unusual process creation with elevated privileges
- Suspicious driver access patterns
- Security log events showing privilege escalation
Network Indicators:
- Lateral movement following local privilege escalation
SIEM Query:
EventID=4688 AND NewProcessName contains * AND SubjectUserName != SYSTEM AND TokenElevationType != %%1936