CVE-2023-33671
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda AC8 routers via a stack overflow in the saveParentControlInfo function. Attackers can exploit this by sending specially crafted requests containing malicious deviceId parameters. This affects users running vulnerable firmware versions on Tenda AC8 routers.
💻 Affected Systems
- Tenda AC8 router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing remote code execution, enabling attackers to take full control of the router, intercept network traffic, pivot to internal networks, or install persistent malware.
Likely Case
Remote code execution leading to router compromise, allowing attackers to modify DNS settings, intercept credentials, or use the router as a foothold for further attacks.
If Mitigated
Limited impact if the router is behind a firewall with strict inbound filtering, though internal attackers could still exploit it.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories, making exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for AC8 router. 3. Log into router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable Parent Control Feature
allDisable the parent control functionality that contains the vulnerable saveParentControlInfo function
Network Segmentation
allPlace the router in a DMZ or isolated network segment to limit potential damage
🧯 If You Can't Patch
- Replace the router with a different model from a vendor that provides security updates
- Implement strict network access controls to limit who can access the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System ToolsCheck Version:
Login to router web interface and check System Status pageVerify Fix Applied:
Verify firmware version has been updated to a version later than V16.03.34.06📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to parent control endpoints
- Multiple failed login attempts followed by exploitation attempts
- Unexpected process crashes or restarts
Network Indicators:
- Unusual outbound connections from router
- DNS hijacking or unexpected redirects
- Traffic interception patterns
SIEM Query:
source="router_logs" AND (uri="/goform/saveParentControlInfo" OR message="deviceId" AND length>100)