CVE-2024-21357
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Windows systems by sending specially crafted PGM (Pragmatic General Multicast) packets. It affects Windows systems with PGM enabled, primarily servers using multicast messaging features. Attackers could gain SYSTEM-level privileges on compromised systems.
💻 Affected Systems
- Windows Server
- Windows Desktop
📦 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 21h1 by Microsoft
Windows 10 21h1 by Microsoft
Windows 10 21h1 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
Windows 11 23h2 by Microsoft
Windows 11 23h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with SYSTEM privileges, enabling complete control over affected systems, data theft, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution leading to malware deployment, ransomware installation, or system takeover for botnet participation.
If Mitigated
No impact if systems are patched or PGM is disabled on internet-facing interfaces.
🎯 Exploit Status
Exploitation requires network access to PGM-enabled systems. No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: February 2024 security updates
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21357
Restart Required: Yes
Instructions:
1. Apply February 2024 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS or SCCM. 3. Verify update installation and restart systems as required.
🔧 Temporary Workarounds
Disable PGM Protocol
windowsDisable the Pragmatic General Multicast protocol on affected systems
netsh int ipv4 set int "InterfaceName" rtm=disable
netsh int ipv6 set int "InterfaceName" rtm=disable
Block PGM Ports
allBlock PGM traffic at network perimeter
🧯 If You Can't Patch
- Disable PGM on all affected systems
- Implement network segmentation to isolate PGM traffic
🔍 How to Verify
Check if Vulnerable:
Check if PGM is enabled: netsh int ipv4 show int | findstr "PGM"Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify February 2024 security updates are installed: wmic qfe list | findstr "KB"📡 Detection & Monitoring
Log Indicators:
- Windows Security Event ID 4688 with suspicious process creation
- Unexpected PGM protocol activity in network logs
Network Indicators:
- Unusual PGM traffic patterns
- PGM packets from unexpected sources
SIEM Query:
EventID=4688 AND (ProcessName contains "cmd.exe" OR ProcessName contains "powershell.exe") AND ParentProcessName contains "svchost.exe"