CVE-2024-51247
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on Draytek Vigor3900 routers by injecting malicious commands into the mainfunction.cgi endpoint. Attackers can achieve remote code execution with high privileges, affecting all organizations using the vulnerable firmware version.
💻 Affected Systems
- Draytek Vigor3900
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router leading to network takeover, data exfiltration, lateral movement to internal systems, and persistent backdoor installation.
Likely Case
Router compromise allowing traffic interception, credential theft, network reconnaissance, and potential pivot to internal systems.
If Mitigated
Limited impact if network segmentation isolates the router and strict access controls prevent exploitation attempts.
🎯 Exploit Status
The GitHub reference contains technical details and proof-of-concept information. Authentication may be required but could be bypassed if default credentials are used.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown - Check Draytek security advisories
Restart Required: Yes
Instructions:
1. Check Draytek website for security advisories
2. Download latest firmware if available
3. Backup current configuration
4. Upload and apply new firmware
5. Restart router
6. Restore configuration if needed
🔧 Temporary Workarounds
Disable Web Management
allDisable web-based management interface to prevent exploitation via mainfunction.cgi
Restrict Access Controls
allImplement strict firewall rules to limit access to router management interface
🧯 If You Can't Patch
- Isolate the router in a dedicated VLAN with strict access controls
- Implement network monitoring for suspicious traffic to/from the router
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface at System Maintenance > Firmware InformationCheck Version:
Check via web interface or SSH: show versionVerify Fix Applied:
Verify firmware version is updated beyond 1.5.1.3📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to mainfunction.cgi
- Command execution patterns in web logs
- Failed authentication attempts to management interface
Network Indicators:
- Suspicious outbound connections from router
- Unexpected traffic patterns
- Port scanning originating from router
SIEM Query:
source="router_logs" AND (uri="*mainfunction.cgi*" OR command="*doPPPo*")