CVE-2023-21689
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on systems running Microsoft's Protected Extensible Authentication Protocol (PEAP) without authentication. It affects Windows systems with PEAP enabled, potentially allowing complete system compromise.
💻 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 1809 by Microsoft
Windows 10 20h2 by Microsoft
Windows 10 20h2 by Microsoft
Windows 10 20h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 21h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 10 22h2 by Microsoft
Windows 11 21h2 by Microsoft
Windows 11 21h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 22h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, enabling data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Remote code execution leading to credential harvesting, lateral movement within networks, or installation of malware.
If Mitigated
Limited impact if network segmentation isolates PEAP servers and strict access controls are enforced.
🎯 Exploit Status
CVSS 9.8 indicates critical severity with network-accessible, unauthenticated exploitation possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: January 2023 security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21689
Restart Required: Yes
Instructions:
1. Apply January 2023 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or SCCM. 3. Verify update installation and restart systems.
🔧 Temporary Workarounds
Disable PEAP authentication
windowsTemporarily disable PEAP authentication until patches can be applied
netsh wlan set profileparameter name="ProfileName" authentication=WPA2PSK
Network segmentation
allIsolate PEAP servers from untrusted networks using firewalls
🧯 If You Can't Patch
- Implement strict network segmentation to isolate PEAP servers
- Deploy intrusion detection systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check if January 2023 security updates are installed via 'wmic qfe list' or Windows Update historyCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify KB5022282 (or later) is installed and system has been restarted📡 Detection & Monitoring
Log Indicators:
- Unusual PEAP authentication failures
- Unexpected process creation from network service accounts
Network Indicators:
- Malformed PEAP packets
- Unexpected connections to PEAP ports (UDP 1812/1813)
SIEM Query:
source="windows" AND (event_id=4625 OR event_id=4688) AND process_name="*" AND user="NETWORK SERVICE"