CVE-2021-38278
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda AC10-1200 routers via a buffer overflow in the saveParentControlInfo function. Attackers can exploit this by sending specially crafted requests to the vulnerable parameter, potentially gaining full control of affected devices. This affects users running the vulnerable firmware version on these routers.
💻 Affected Systems
- Tenda AC10-1200
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router compromise, allowing attackers to intercept traffic, modify DNS settings, install malware, pivot to internal networks, or create persistent backdoors.
Likely Case
Router takeover enabling traffic interception, credential theft, network reconnaissance, and potential lateral movement to connected devices.
If Mitigated
Limited impact with proper network segmentation, though the router itself remains vulnerable to compromise.
🎯 Exploit Status
Public proof-of-concept demonstrates exploitation via strcpy buffer overflow. Exploitation requires network access to the router's web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. If update available, download and upload via web interface
3. Reboot router after update
4. Verify firmware version changed
🔧 Temporary Workarounds
Disable web management interface
allPrevent external access to vulnerable interface
Access router settings → Administration → Remote Management → Disable
Network segmentation
allIsolate router management interface from untrusted networks
Configure firewall rules to restrict access to router IP on port 80/443
🧯 If You Can't Patch
- Replace affected router with different model/brand
- Place router behind dedicated firewall with strict access controls
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: Login → System Tools → Firmware UpgradeCheck Version:
curl -s http://router-ip/ | grep -i firmware || nmap -sV -p80,443 router-ipVerify Fix Applied:
Verify firmware version is different from v15.03.06.23_EN📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/saveParentControlInfo
- Large payloads in URLs parameter
- Multiple failed authentication attempts followed by exploitation attempts
Network Indicators:
- Unusual traffic to router management interface from external IPs
- POST requests with abnormally long URLs parameter
SIEM Query:
source="router_logs" AND (uri_path="/goform/saveParentControlInfo" OR "urls" IN request_body)