CVE-2023-41562
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on affected Tenda routers via a stack overflow in the PowerSaveSet function. Attackers can exploit this by sending specially crafted requests to the /goform/PowerSaveSet endpoint. Users of specific Tenda router models with vulnerable firmware versions are affected.
💻 Affected Systems
- Tenda AC7
- Tenda AC9
- Tenda AC5
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router leading to persistent backdoor installation, network traffic interception, lateral movement to internal devices, and botnet recruitment.
Likely Case
Router takeover allowing attackers to modify DNS settings, intercept traffic, disable security features, and use the device for further attacks.
If Mitigated
Limited impact if routers are behind firewalls with strict inbound filtering and network segmentation prevents lateral movement.
🎯 Exploit Status
Public proof-of-concept exists in GitHub repositories. Exploitation requires sending HTTP POST request with malicious time parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None found
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware for your model. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router admin interface
Firewall blocking
linuxBlock access to /goform/PowerSaveSet endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/goform/PowerSaveSet" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/goform/PowerSaveSet" --algo bm -j DROP
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict firewall rules
- Implement network monitoring for exploitation attempts and anomalous router behavior
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or Firmware Upgrade sectionCheck Version:
curl -s http://router-ip/goform/getStatus | grep version or check web interfaceVerify Fix Applied:
Verify firmware version has been updated to a version later than those listed in affected systems📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/PowerSaveSet with unusually long time parameter
- Router crash/reboot logs
- Unusual process execution in router logs
Network Indicators:
- HTTP traffic to router on port 80/443 with PowerSaveSet in URI
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND uri="/goform/PowerSaveSet" AND method="POST"