CVE-2021-24074
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Windows systems by sending specially crafted TCP/IP packets. It affects Windows operating systems with TCP/IP networking enabled, potentially impacting servers and workstations.
💻 Affected Systems
- Windows 10
- Windows Server 2019
- Windows Server 2016
- Windows Server, version 1903
- Windows Server, version 1909
- Windows Server, version 2004
- Windows Server, version 20H2
📦 What is this software?
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 10 by Microsoft
Windows 7 by Microsoft
Windows 8.1 by Microsoft
Windows Rt 8.1 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM-level privileges, enabling attackers to install malware, steal data, or create persistent backdoors.
Likely Case
Remote code execution leading to ransomware deployment, data exfiltration, or lateral movement within networks.
If Mitigated
Limited impact with proper network segmentation, firewalls, and endpoint protection blocking exploitation attempts.
🎯 Exploit Status
Exploitation requires sending specially crafted TCP/IP packets to vulnerable systems. The vulnerability is in the TCP/IP stack implementation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: February 2021 security updates
Vendor Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-24074
Restart Required: Yes
Instructions:
1. Apply February 2021 Windows security updates. 2. Use Windows Update or download from Microsoft Update Catalog. 3. Restart system after installation.
🔧 Temporary Workarounds
Disable IPv6
windowsDisabling IPv6 may reduce attack surface but doesn't fully mitigate the vulnerability
netsh interface teredo set state disabled
netsh interface ipv6 set state disabled
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy network intrusion prevention systems to detect and block exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for February 2021 security updates or use systeminfo command to check OS build numberCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify KB5001027 (or later) is installed via Windows Update history or systeminfo📡 Detection & Monitoring
Log Indicators:
- Windows Security Event logs showing unexpected process creation
- System logs with TCP/IP stack errors
Network Indicators:
- Unusual TCP/IP traffic patterns
- Malformed packets targeting Windows systems
SIEM Query:
source="windows" AND (event_id=4688 OR event_id=1) AND process_name="cmd.exe" OR process_name="powershell.exe"