CVE-2023-41560
📋 TL;DR
CVE-2023-41560 is a critical stack-based buffer overflow vulnerability in Tenda AC9 routers that allows remote attackers to execute arbitrary code by sending specially crafted requests to the /goform/SetFirewallCfg endpoint. This affects Tenda AC9 V3.0 routers running firmware version V15.03.06.42_multi. Attackers can potentially gain full control of affected routers.
💻 Affected Systems
- Tenda AC9 V3.0
📦 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 allowing DNS hijacking, credential harvesting, and botnet recruitment for DDoS attacks.
If Mitigated
Limited impact if network segmentation isolates router management interface and proper access controls are implemented.
🎯 Exploit Status
Public proof-of-concept code demonstrates exploitation via HTTP POST requests to the vulnerable endpoint. No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda support for firmware updates. 2. If update available, download from official Tenda website. 3. Log into 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 web interface
Network Segmentation
allIsolate router management interface from untrusted networks
🧯 If You Can't Patch
- Replace affected routers with patched or different models
- Implement strict firewall rules blocking access to port 80/443 on router WAN interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via admin interface at System Status or About page. If version is V15.03.06.42_multi, device is vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep version or check web interfaceVerify Fix Applied:
Verify firmware version has changed from V15.03.06.42_multi to a newer version after update.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetFirewallCfg with large firewallEn parameter
- Unusual process execution or memory errors in router logs
Network Indicators:
- HTTP traffic to router IP on port 80/443 with POST to vulnerable endpoint
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND (uri="/goform/SetFirewallCfg" OR method="POST" AND uri CONTAINS "SetFirewallCfg")