CVE-2024-33835
📋 TL;DR
This CVE describes a stack overflow vulnerability in Tenda AC18 routers that allows remote attackers to execute arbitrary code by sending specially crafted requests to the vulnerable parameter. The vulnerability affects Tenda AC18 routers running firmware version V15.03.05.05. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Tenda AC18
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full root shell access to the router, enabling them to intercept all network traffic, install persistent malware, pivot to internal networks, and brick the device.
Likely Case
Remote attacker executes arbitrary code with root privileges, potentially creating a botnet node, intercepting credentials, or modifying router configuration.
If Mitigated
With proper network segmentation and firewall rules, impact is limited to the router itself, though device compromise still allows traffic interception and lateral movement attempts.
🎯 Exploit Status
The GitHub reference contains technical details about the vulnerability and exploitation method. Stack overflow vulnerabilities in embedded devices are frequently weaponized due to their remote, unauthenticated nature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for AC18. 3. Access router web interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Wait for router to reboot.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the vulnerable web management interface
Access router web interface > System Tools > Remote Management > Disable
Restrict Management Interface Access
allLimit access to router management interface to trusted IPs only
Access router web interface > Security > Firewall > Add rule to block WAN access to management ports
🧯 If You Can't Patch
- Isolate the router in a separate VLAN with strict firewall rules preventing internet access to management interfaces
- Implement network monitoring for unusual traffic patterns or exploit attempts targeting the router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: System Status > Firmware Version. If version is V15.03.05.05, device is vulnerable.Check Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
After updating firmware, verify version is no longer V15.03.05.05. Test by attempting to access the vulnerable endpoint with proper security testing tools.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to formSetSafeWanWebMan endpoint
- Large payloads sent to remoteIp parameter
- Router reboot events following suspicious requests
Network Indicators:
- HTTP POST requests to /goform/setSafeWanWebMan with oversized remoteIp parameter
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND (uri_path="/goform/setSafeWanWebMan" AND remoteIp.length>100)