CVE-2024-41339
📋 TL;DR
This vulnerability allows attackers to upload malicious kernel modules through the CGI configuration upload endpoint in affected Draytek routers, leading to arbitrary code execution with root privileges. It affects multiple Draytek Vigor router models running vulnerable firmware versions. Attackers can gain complete control of the router if successfully exploited.
💻 Affected Systems
- Draytek Vigor 165
- Draytek Vigor 166
- Draytek Vigor 2620
- Draytek Vigor LTE200
- Draytek Vigor 2860
- Draytek Vigor 2925
- Draytek Vigor 2862
- Draytek Vigor 2926
- Draytek Vigor 2133
- Draytek Vigor 2762
- Draytek Vigor 2832
- Draytek Vigor 2135
- Draytek Vigor 2765
- Draytek Vigor 2766
- Draytek Vigor 2865
- Draytek Vigor 2866
- Draytek Vigor 2927
- Draytek Vigor 2962
- Draytek Vigor 3910
- Draytek Vigor 3912
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attackers to intercept all network traffic, pivot to internal networks, install persistent backdoors, and use the router as a botnet node.
Likely Case
Router takeover enabling traffic interception, credential theft, and lateral movement into connected networks.
If Mitigated
Limited impact if proper network segmentation and access controls prevent external access to router management interfaces.
🎯 Exploit Status
Exploitation requires access to the router's web management interface. The vulnerability is in the configuration upload functionality.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Varies by model - see description for specific fixed versions per device
Vendor Advisory: http://draytek.com
Restart Required: Yes
Instructions:
1. Identify your router model and current firmware version. 2. Visit Draytek's support website. 3. Download the appropriate firmware update for your model. 4. Log into router web interface. 5. Navigate to System Maintenance > Firmware Upgrade. 6. Upload and apply the firmware update. 7. Reboot the router.
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to the router's web management interface to trusted IP addresses only
Disable Remote Management
allTurn off WAN-side access to the management interface if not required
🧯 If You Can't Patch
- Segment router management interface to isolated VLAN with strict access controls
- Implement network monitoring for suspicious upload attempts to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface and compare against vulnerable versions listed in CVE descriptionCheck Version:
Login to router web interface and navigate to System Maintenance > Firmware InformationVerify Fix Applied:
Verify firmware version has been updated to patched version via web interface System Status page📡 Detection & Monitoring
Log Indicators:
- Multiple failed upload attempts to CGI endpoints
- Successful configuration uploads from unusual IP addresses
- Kernel module loading events
Network Indicators:
- HTTP POST requests to /cgi-bin/*upload* endpoints from external IPs
- Unusual outbound connections from router after upload activity
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/*upload*" OR event="firmware_upload" OR event="config_upload")