CVE-2025-21379
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected systems by sending specially crafted DHCP packets to the DHCP client service. It affects Windows systems with the DHCP client enabled, potentially allowing attackers to gain SYSTEM privileges on compromised machines.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Windows 11 24h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with SYSTEM privileges, enabling complete control over the affected system, lateral movement, and data exfiltration.
Likely Case
Initial foothold for attackers leading to privilege escalation, persistence establishment, and deployment of additional payloads.
If Mitigated
Limited impact due to network segmentation, host-based firewalls, and proper patch management preventing exploitation.
🎯 Exploit Status
Exploitation requires sending malicious DHCP packets to the target's DHCP client. No authentication is required, but the attacker must be on the same network segment or able to route packets to the target.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security updates released in March 2025 Patch Tuesday
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21379
Restart Required: Yes
Instructions:
1. Apply the March 2025 security updates from Microsoft. 2. Restart the system to complete the installation. 3. Verify the patch is applied using Windows Update or system version checks.
🔧 Temporary Workarounds
Disable DHCP Client Service
WindowsDisables the vulnerable DHCP client service, preventing exploitation but breaking automatic network configuration.
sc config dhcp start= disabled
sc stop dhcp
Use Static IP Configuration
allConfigure static IP addresses instead of DHCP to reduce attack surface while keeping the service available.
🧯 If You Can't Patch
- Implement network segmentation to isolate DHCP traffic to trusted segments only
- Deploy host-based firewalls to block incoming DHCP packets from untrusted sources
🔍 How to Verify
Check if Vulnerable:
Check if the system has the March 2025 security updates installed via Windows Update or systeminfo command.Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify the security update KB number for March 2025 is listed in installed updates and the system has been restarted.📡 Detection & Monitoring
Log Indicators:
- Unusual DHCP packet processing errors in System logs
- DHCP client service crashes or unexpected restarts
Network Indicators:
- Malformed DHCP packets from unexpected sources
- DHCP traffic to systems that shouldn't be using DHCP
SIEM Query:
EventID=1000 OR EventID=1001 Source="Dhcp" AND (Keywords="Error" OR Keywords="Critical")