CVE-2024-37640
📋 TL;DR
This vulnerability is a stack overflow in the TOTOLINK A3700R router's setWiFiEasyGuestCfg function, allowing remote attackers to execute arbitrary code by sending specially crafted requests to the ssid5g parameter. It affects users of TOTOLINK A3700R routers running vulnerable firmware versions. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- TOTOLINK A3700R
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full router compromise, enabling attacker to intercept traffic, modify configurations, install persistent backdoors, or pivot to internal networks.
Likely Case
Router crash/reboot causing denial of service, potentially followed by remote code execution if exploit is refined.
If Mitigated
Limited to denial of service if input validation or stack protection is present, but still disruptive.
🎯 Exploit Status
Proof of concept available in GitHub repository. Exploitation requires authentication to router management interface. Stack overflow vulnerabilities in embedded devices often lead to reliable exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not found in provided references
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware for A3700R. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable WiFi Easy Guest feature
allTurn off the vulnerable WiFi Easy Guest configuration function to prevent exploitation.
Access router web interface > WiFi Settings > Guest Network > Disable Easy Guest feature
Restrict management interface access
allLimit access to router management interface to trusted IP addresses only.
Access router web interface > Security/Firewall > Management Access Control > Add allowed IP ranges
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules limiting inbound/outbound traffic
- Implement network monitoring for unusual traffic patterns or connection attempts to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface: System Tools > Firmware Upgrade. If version is V9.1.2u.6165_20211012 or similar, likely vulnerable.Check Version:
curl -s http://router-ip/version or check web interfaceVerify Fix Applied:
After firmware update, verify version has changed from vulnerable version. Test WiFi Easy Guest functionality to ensure it works without crashes.📡 Detection & Monitoring
Log Indicators:
- Repeated router reboots/crashes
- Unusual authentication attempts to management interface
- Large payloads sent to setWiFiEasyGuestCfg endpoint
Network Indicators:
- Unusual traffic patterns to router management port (typically 80/443)
- Exploit payload patterns in HTTP requests
SIEM Query:
source="router.log" AND ("setWiFiEasyGuestCfg" OR "ssid5g" AND payload_size>threshold)