CVE-2024-51304
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on Draytek Vigor3900 routers by injecting malicious commands into the mainfunction.cgi component. Attackers can exploit improper input validation in the ldap_search_dn function to achieve remote code execution. Organizations using affected Draytek Vigor3900 routers are at risk.
💻 Affected Systems
- Draytek Vigor3900
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to pivot to internal networks, intercept traffic, install persistent backdoors, or use the device as part of a botnet.
Likely Case
Attackers gain shell access to the router, enabling them to modify configurations, steal credentials, or use the device for further attacks.
If Mitigated
Limited impact if network segmentation isolates the router and proper monitoring detects exploitation attempts.
🎯 Exploit Status
The GitHub reference contains technical details that could facilitate exploitation. The vulnerability requires no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
Check Draytek's official website for firmware updates. If available, download the latest firmware and apply through the router's web interface under System Maintenance > Firmware Upgrade.
🔧 Temporary Workarounds
Disable LDAP functionality
allIf LDAP authentication is not required, disable it in the router's configuration to remove the attack surface.
Restrict web interface access
allConfigure firewall rules to restrict access to the router's web management interface to trusted IP addresses only.
🧯 If You Can't Patch
- Isolate the router in a dedicated network segment with strict firewall rules limiting inbound and outbound connections.
- Implement network monitoring and intrusion detection specifically for the router's management interface traffic.
🔍 How to Verify
Check if Vulnerable:
Check the firmware version in the router's web interface under System Maintenance > Firmware Information. If version is 1.5.1.3, the device is vulnerable.Check Version:
No CLI command available. Must check through web interface at System Maintenance > Firmware Information.Verify Fix Applied:
After applying any firmware update, verify the version has changed from 1.5.1.3 to a newer version.📡 Detection & Monitoring
Log Indicators:
- Unusual LDAP search requests in router logs
- Multiple failed authentication attempts followed by successful LDAP queries
- Unexpected command execution patterns in system logs
Network Indicators:
- HTTP POST requests to /cgi-bin/mainfunction.cgi with suspicious parameters
- Unusual outbound connections from the router to external IPs
SIEM Query:
source="vigor3900" AND (url="/cgi-bin/mainfunction.cgi" OR message="ldap_search_dn")