CVE-2023-50985
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda i29 routers via a buffer overflow in the lanCfgSet function. Attackers can exploit this by sending specially crafted requests to the lanGw parameter. All users running the vulnerable firmware version are affected.
💻 Affected Systems
- Tenda i29
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, and lateral movement to other devices on the network.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Public proof-of-concept exists in GitHub repository; buffer overflow vulnerabilities in network devices are commonly weaponized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://tenda.com
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware. 3. Access router admin interface. 4. Upload and install new firmware. 5. Reboot router.
🔧 Temporary Workarounds
Disable remote administration
allPrevent external access to router administration interface
Network segmentation
allIsolate router management interface to trusted network segment only
🧯 If You Can't Patch
- Replace affected device with updated model or different vendor
- Implement strict firewall rules to block all WAN access to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface; if version is V1.0.0.5, device is vulnerable.Check Version:
Check via router web interface at 192.168.0.1 or 192.168.1.1Verify Fix Applied:
Verify firmware version has been updated to a version later than V1.0.0.5.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to lanCfgSet endpoint
- Multiple failed buffer overflow attempts
- Unexpected router configuration changes
Network Indicators:
- Unusual traffic patterns to router management interface
- Exploit payloads in HTTP requests to router
SIEM Query:
source_ip=external AND dest_ip=router_ip AND (uri_path CONTAINS 'lanCfgSet' OR http_method='POST' AND user_agent='exploit')