CVE-2024-41590
📋 TL;DR
This vulnerability allows authenticated users to exploit buffer overflows in CGI endpoints on DrayTek Vigor310 devices by sending specially crafted POST requests. Attackers could potentially execute arbitrary code or crash the device. Only DrayTek Vigor310 devices running firmware through version 4.3.2.6 are affected.
💻 Affected Systems
- DrayTek Vigor310
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, network pivoting, and persistent backdoor installation.
Likely Case
Device crash causing denial of service, potentially requiring physical reset or firmware reflash.
If Mitigated
Limited to denial of service if proper network segmentation and authentication controls are in place.
🎯 Exploit Status
Exploitation requires authentication but buffer overflow via strcpy is a well-understood vulnerability class with mature exploitation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.3.2.7 or later
Vendor Advisory: https://www.draytek.com/support/security-advisory/
Restart Required: Yes
Instructions:
1. Log into Vigor310 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.
🔧 Temporary Workarounds
Disable CGI endpoints
allIf possible, disable unused CGI endpoints through device configuration
Network segmentation
allIsolate Vigor310 devices from untrusted networks and restrict access to management interfaces
🧯 If You Can't Patch
- Implement strict access controls to limit which users can authenticate to the device
- Monitor for abnormal POST requests to CGI endpoints and implement rate limiting
🔍 How to Verify
Check if Vulnerable:
Check firmware version in web interface: System Maintenance > Firmware InformationCheck Version:
No CLI command - check via web interface or SNMP if configuredVerify Fix Applied:
Verify firmware version is 4.3.2.7 or higher after update📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by large POST requests
- Device crash/reboot logs
- Unusual CGI endpoint access
Network Indicators:
- Large POST requests to CGI endpoints
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="vigor310" AND (http_method="POST" AND uri="*.cgi" AND content_length>1000)