CVE-2025-53137
📋 TL;DR
This vulnerability allows an authorized attacker to exploit a use-after-free flaw in Windows Ancillary Function Driver for WinSock to elevate privileges locally. It affects Windows systems where an attacker already has some level of access and can execute code. The impact is limited to local privilege escalation rather than remote code execution.
💻 Affected Systems
- Microsoft Windows
📦 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 with initial access (e.g., as a standard user) gains SYSTEM/administrator privileges, enabling complete system compromise, data theft, persistence installation, and lateral movement.
Likely Case
Malware or an attacker with user-level access escalates to administrative privileges to bypass security controls, install backdoors, or access sensitive data.
If Mitigated
With proper controls like least privilege, application whitelisting, and patch management, impact is reduced to isolated privilege escalation attempts that are detected and contained.
🎯 Exploit Status
Exploitation requires local access and knowledge of driver internals; use-after-free bugs often require precise timing and memory manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers and versions.
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53137
Restart Required: Yes
Instructions:
1. Open Windows Update Settings. 2. Click 'Check for updates'. 3. Install all available security updates. 4. Restart the system if prompted. For enterprise: Deploy via WSUS, SCCM, or Microsoft Endpoint Manager.
🔧 Temporary Workarounds
Restrict local access
windowsLimit user accounts and applications to least privilege to reduce attack surface for local privilege escalation.
🧯 If You Can't Patch
- Implement strict access controls and monitor for suspicious privilege escalation attempts.
- Use application control solutions to block unauthorized code execution.
🔍 How to Verify
Check if Vulnerable:
Check system for the presence of the vulnerable driver version; exact method depends on patch details from Microsoft.Check Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify that Windows Update shows the latest security patches installed and system is restarted.📡 Detection & Monitoring
Log Indicators:
- Event ID 4688 (process creation) showing privilege escalation, unexpected driver loads (afd.sys anomalies).
Network Indicators:
- None directly; this is a local exploit.
SIEM Query:
Example: EventID=4688 AND NewProcessName contains 'cmd.exe' AND SubjectUserName != 'SYSTEM' AND TokenElevationType != '%%1936'