CVE-2024-38148
📋 TL;DR
This vulnerability in Windows Secure Channel allows attackers to cause a denial of service by sending specially crafted packets to vulnerable systems. It affects Windows servers and workstations running affected versions. The vulnerability could cause system instability or crashes.
💻 Affected Systems
- Microsoft Windows
📦 What is this software?
Windows 11 21h2 by Microsoft
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash requiring reboot, potentially disrupting critical services and causing downtime.
Likely Case
Service disruption affecting Secure Channel functionality, potentially impacting authentication or secure communications.
If Mitigated
Minimal impact with proper network segmentation and monitoring in place.
🎯 Exploit Status
Exploitation requires sending specially crafted packets to vulnerable systems. No authentication is required, but the attacker needs network access to the target.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: July 2024 security updates (KB5040442 for Windows 11, KB5040437 for Windows 10, etc.)
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-38148
Restart Required: Yes
Instructions:
1. Apply the July 2024 Windows security updates via Windows Update. 2. For enterprise environments, deploy updates through WSUS, SCCM, or Intune. 3. Restart systems after patch installation.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to systems using Secure Channel to trusted sources only.
Firewall Rules
windowsBlock unnecessary inbound traffic to Secure Channel ports (typically 443/TLS, 3389/RDP with TLS).
netsh advfirewall firewall add rule name="Block Schannel Exploit" dir=in action=block protocol=TCP localport=443,3389
🧯 If You Can't Patch
- Implement strict network segmentation to limit exposure of vulnerable systems
- Deploy intrusion detection/prevention systems to monitor for exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check Windows version and patch level. Systems without July 2024 security updates are vulnerable.Check Version:
wmic os get caption,version,buildnumberVerify Fix Applied:
Verify that July 2024 security updates are installed via 'wmic qfe list' or 'Get-HotFix' in PowerShell.📡 Detection & Monitoring
Log Indicators:
- Event ID 36874 in Windows Security logs indicating Schannel errors
- System crashes or unexpected reboots
Network Indicators:
- Unusual traffic patterns to Secure Channel ports
- Multiple connection attempts with malformed packets
SIEM Query:
source="windows" AND (event_id=36874 OR "Schannel" AND "error")