CVE-2024-43455
📋 TL;DR
This vulnerability allows attackers to spoof the Windows Remote Desktop Licensing Service, potentially enabling them to intercept or manipulate licensing communications. It affects systems running Windows Remote Desktop Licensing Service with vulnerable configurations. Organizations using Remote Desktop Services in enterprise environments are primarily at risk.
💻 Affected Systems
- Windows Remote Desktop Licensing Service
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept licensing communications, potentially enabling unauthorized access to Remote Desktop Services, credential theft, or service disruption across an organization's RDS infrastructure.
Likely Case
Attackers could spoof licensing servers to deliver malicious responses, potentially leading to service disruption or enabling further attacks against RDS clients.
If Mitigated
With proper network segmentation and access controls, the impact is limited to potential service disruption within isolated network segments.
🎯 Exploit Status
Exploitation requires network access to the licensing service and ability to spoof communications. No public exploits have been reported as of analysis date.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers per Windows version
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-43455
Restart Required: Yes
Instructions:
1. Apply the latest Windows security updates from Microsoft. 2. For Windows Server, install updates via Windows Update or WSUS. 3. Restart affected systems after patch installation.
🔧 Temporary Workarounds
Disable Remote Desktop Licensing Service
windowsTemporarily disable the service if not required for operations
sc stop TermServLicensing
sc config TermServLicensing start= disabled
Restrict Network Access
windowsConfigure firewall rules to limit access to Remote Desktop Licensing Service (port 135 and dynamic RPC ports)
New-NetFirewallRule -DisplayName "Block RD Licensing" -Direction Inbound -Protocol TCP -LocalPort 135 -Action Block
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Remote Desktop Licensing servers from untrusted networks
- Monitor network traffic to/from RD Licensing Service for unusual patterns or spoofing attempts
🔍 How to Verify
Check if Vulnerable:
Check if Remote Desktop Licensing Service is running: Get-Service TermServLicensing | Select Status, StartTypeCheck Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify Windows Update history contains the relevant security update and service is restarted📡 Detection & Monitoring
Log Indicators:
- Event ID 4625 (failed logon) from RD Licensing Service
- Unusual authentication patterns in Security logs
- Service control manager events showing RD Licensing service restarts
Network Indicators:
- Unusual traffic patterns to/from port 135 (RPC)
- Suspicious RPC communications to RD Licensing Service
- Multiple failed connection attempts to licensing service
SIEM Query:
source="windows" AND (event_id=4625 OR event_id=4634) AND service_name="TermServLicensing"