CVE-2022-28560
📋 TL;DR
A stack overflow vulnerability in Tenda AC9 routers allows remote attackers to execute arbitrary code via crafted HTTP requests to the goform/fast_setting_wifi_set endpoint. This affects Tenda AC9 router users running vulnerable firmware versions, potentially giving attackers full control of the device.
💻 Affected Systems
- Tenda AC9 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of router with persistent attacker access, network traffic interception, credential theft, and pivot to internal network devices.
Likely Case
Router takeover leading to DNS hijacking, credential harvesting, and installation of persistent malware on the device.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to router admin interface.
🎯 Exploit Status
Public exploit code exists in GitHub repositories. Attack requires sending crafted HTTP POST request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware > 15.03.2.21_cn
Vendor Advisory: Not publicly documented by vendor
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to System Tools > Firmware Upgrade. 3. Download latest firmware from Tenda website. 4. Upload and install firmware. 5. Reboot router after installation.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router admin interface
Login to router > Advanced > System Tools > Remote Management > Disable
Block Vulnerable Endpoint
linuxUse router firewall to block access to goform/fast_setting_wifi_set
iptables -A INPUT -p tcp --dport 80 -m string --string "goform/fast_setting_wifi_set" --algo bm -j DROP
🧯 If You Can't Patch
- Segment router management interface to internal network only
- Implement network-based intrusion detection to monitor for exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status. If version is 15.03.2.21_cn or earlier, assume vulnerable.Check Version:
curl -s http://router-ip/goform/GetModuleStatus | grep versionVerify Fix Applied:
Verify firmware version is updated beyond 15.03.2.21_cn and test if goform/fast_setting_wifi_set endpoint still accepts malformed requests.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/fast_setting_wifi_set with large payloads
- Unusual process creation from httpd service
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST to vulnerable endpoint
- Sudden outbound connections from router to unknown IPs
SIEM Query:
source="router_logs" AND (uri="/goform/fast_setting_wifi_set" OR method="POST" AND uri CONTAINS "fast_setting_wifi_set")