CVE-2023-40798
📋 TL;DR
This vulnerability in Tenda AC23 routers allows authenticated attackers to execute arbitrary code via stack overflow in IPv6 and WAN parameter functions. It affects users running vulnerable firmware versions, potentially compromising router security and network integrity.
💻 Affected Systems
- Tenda AC23
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise leading to persistent backdoor installation, network traffic interception, lateral movement to connected devices, and botnet recruitment.
Likely Case
Router takeover allowing configuration changes, DNS hijacking, credential theft from network traffic, and denial of service to connected devices.
If Mitigated
Limited impact if strong network segmentation isolates the router and regular credential rotation prevents attacker persistence.
🎯 Exploit Status
Exploit requires valid admin credentials; published PoC demonstrates reliable exploitation.
🛠️ 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 source. 3. Backup router configuration. 4. Upload firmware via admin interface. 5. Factory reset after update. 6. Restore minimal configuration.
🔧 Temporary Workarounds
Disable IPv6
allPrevents exploitation via formSetIPv6status function
Login to router admin → Network → IPv6 → Disable
Change Admin Credentials
allMitigates authentication requirement for exploit
Login to router admin → System Tools → Modify Login Password
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules
- Implement network monitoring for unusual router traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status → Firmware VersionCheck Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version is newer than v16.03.07.45_cn and test IPv6/WAN functions📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful login and configuration changes
- Unusual POST requests to /goform/setIPv6status or /goform/getWanParameter
Network Indicators:
- Unexpected outbound connections from router
- DNS queries to suspicious domains
- Port scanning originating from router
SIEM Query:
source="router.log" AND (uri="/goform/setIPv6status" OR uri="/goform/getWanParameter") AND status=200