CVE-2024-43027
📋 TL;DR
This CVE describes a command injection vulnerability in DrayTek router firmware that allows attackers to execute arbitrary commands on affected devices. Attackers can exploit this by sending specially crafted requests to the cgi-bin/mainfunction.cgi endpoint. Organizations using affected DrayTek router models with vulnerable firmware versions are at risk.
💻 Affected Systems
- DrayTek Vigor 3900
- DrayTek Vigor 2960
- DrayTek Vigor 300B
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to execute arbitrary commands with root privileges, potentially leading to network takeover, data exfiltration, or use as a pivot point into internal networks.
Likely Case
Remote code execution leading to device compromise, credential theft, network traffic interception, or installation of persistent backdoors.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation prevents lateral movement.
🎯 Exploit Status
The GitHub reference contains technical details and appears to demonstrate exploitation. Command injection vulnerabilities in network devices are commonly weaponized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v1.5.1.5_Beta or later
Vendor Advisory: https://www.draytek.com/support/security-advisory/
Restart Required: Yes
Instructions:
1. Log into DrayTek router web interface. 2. Navigate to System Maintenance > Firmware Upgrade. 3. Download latest firmware from DrayTek support site. 4. Upload and apply firmware update. 5. Reboot device after update completes.
🔧 Temporary Workarounds
Restrict Web Management Access
allLimit access to router web management interface to trusted IP addresses only
Configure firewall rules to restrict access to router management IP/ports
Disable Remote Management
allDisable web management interface from WAN/external interfaces
Navigate to System Maintenance > Management > disable 'Enable Web Config from WAN'
🧯 If You Can't Patch
- Isolate affected routers in dedicated network segments with strict firewall rules
- Implement network monitoring and IDS/IPS rules to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface under System Maintenance > Firmware InformationCheck Version:
Check via web interface or SSH: show versionVerify Fix Applied:
Confirm firmware version is v1.5.1.5_Beta or later in System Maintenance > Firmware Information📡 Detection & Monitoring
Log Indicators:
- Unusual CGI requests to mainfunction.cgi
- Suspicious command strings in URL parameters
- Failed authentication attempts followed by CGI access
Network Indicators:
- HTTP requests to /cgi-bin/mainfunction.cgi with unusual action parameters
- Traffic patterns suggesting command injection attempts
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/mainfunction.cgi" AND (param="action" AND value CONTAINS "|" OR value CONTAINS ";" OR value CONTAINS "$"))