CVE-2022-30476
📋 TL;DR
This critical vulnerability in Tenda AC Series routers allows remote attackers to execute arbitrary code via a stack-based buffer overflow in the httpd module. Attackers can exploit this by sending specially crafted requests to the /goform/SetFirewallCfg endpoint, potentially gaining full control of affected routers. All users of Tenda AC18 routers with vulnerable firmware are affected.
💻 Affected Systems
- Tenda AC Series Router AC18
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise leading to persistent backdoor installation, credential theft, network traffic interception, and pivot point for attacking internal network devices.
Likely Case
Router takeover enabling DNS hijacking, credential harvesting, and botnet recruitment for DDoS attacks.
If Mitigated
Limited impact if routers are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not publicly available
Restart Required: Yes
Instructions:
1. Check Tenda support website for firmware updates. 2. Download latest firmware for AC18 router. 3. Access router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router admin interface
Network Segmentation
allIsolate router management interface to trusted network segment
🧯 If You Can't Patch
- Replace vulnerable routers with supported models from different vendors
- Implement strict firewall rules blocking all inbound traffic to router management interfaces
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System ToolsCheck Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version has been updated to a version later than AC18_V15.03.05.19(6318)📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetFirewallCfg with unusually long parameters
- Router crash/restart events in system logs
Network Indicators:
- Unusual outbound connections from router to unknown IPs
- DNS queries to suspicious domains from router
SIEM Query:
source="router.logs" AND (uri="/goform/SetFirewallCfg" AND content_length>1000)