CVE-2024-6146
📋 TL;DR
This vulnerability allows network-adjacent attackers to execute arbitrary code on Actiontec WCB6200Q routers without authentication. The flaw exists in the HTTP server's handling of POST data with file uploads, where improper length validation leads to a stack-based buffer overflow. Attackers on the same network can exploit this to gain remote code execution.
💻 Affected Systems
- Actiontec WCB6200Q
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to install persistent malware, intercept all network traffic, pivot to internal networks, and brick the device.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, and deployment of botnet malware.
If Mitigated
Limited impact if network segmentation isolates the router and intrusion detection systems block exploitation attempts.
🎯 Exploit Status
No authentication required, network-adjacent access needed. ZDI has technical details but no public exploit code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Actiontec for latest firmware
Vendor Advisory: https://www.actiontec.com/support/security-advisories/
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to firmware update section. 3. Download latest firmware from Actiontec support site. 4. Upload and apply firmware update. 5. Reboot router.
🔧 Temporary Workarounds
Network Segmentation
allIsolate WCB6200Q router on separate VLAN to limit attack surface
Disable HTTP Management
allUse HTTPS only for management interface if supported
🧯 If You Can't Patch
- Replace with different router model that receives security updates
- Implement strict network access controls to limit who can reach the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface and compare against Actiontec's patched version listCheck Version:
curl -s http://router-ip/status | grep firmware (or check admin web interface)Verify Fix Applied:
Confirm firmware version matches or exceeds patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests with large upload data
- Multiple failed buffer overflow attempts in system logs
- Unexpected process crashes of HTTP server
Network Indicators:
- HTTP requests with abnormally large Content-Length headers
- POST requests to upload endpoints with crafted data
- Network traffic patterns suggesting router compromise
SIEM Query:
source="router_logs" AND (http_method="POST" AND content_length>1000000) OR process="httpd" AND event="segmentation_fault"