CVE-2025-21179
📋 TL;DR
This vulnerability in the DHCP Client Service allows an attacker to cause a denial of service by sending specially crafted DHCP packets. Systems running affected Windows versions with DHCP enabled are vulnerable. The vulnerability could cause the DHCP client service to crash, potentially disrupting network connectivity.
💻 Affected Systems
- Microsoft Windows DHCP Client
📦 What is this software?
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete loss of network connectivity on affected systems requiring manual intervention to restore service
Likely Case
Temporary network disruption until DHCP client service automatically restarts or system is rebooted
If Mitigated
Minimal impact with service restarting automatically or network redundancy in place
🎯 Exploit Status
Exploitation requires network access to send DHCP packets to vulnerable systems
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security updates released in March 2025 monthly security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21179
Restart Required: Yes
Instructions:
1. Apply March 2025 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or Microsoft Endpoint Configuration Manager. 3. Restart affected systems to complete installation.
🔧 Temporary Workarounds
Disable DHCP Client Service
windowsConfigure systems with static IP addresses instead of DHCP
sc config dhcp start= disabled
sc stop dhcp
Network Segmentation
allRestrict DHCP traffic to trusted network segments only
🧯 If You Can't Patch
- Implement network ACLs to restrict DHCP traffic to authorized DHCP servers only
- Monitor for unusual DHCP traffic patterns and implement IDS/IPS rules to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check if system is running affected Windows versions without March 2025 security updates installedCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify March 2025 security updates are installed via Windows Update history or systeminfo command📡 Detection & Monitoring
Log Indicators:
- Event ID 1000 in Application logs for dhcpcore.dll crashes
- Unexpected DHCP client service restarts
Network Indicators:
- Unusual DHCP traffic from non-DHCP server sources
- DHCP packets with malformed options
SIEM Query:
EventID=1000 AND SourceName="Application Error" AND ProcessName="svchost.exe" AND ModuleName="dhcpcore.dll"