CVE-2022-24973
📋 TL;DR
This is a stack-based buffer overflow vulnerability in TP-Link TL-WR940N routers that allows authenticated attackers on the same network to execute arbitrary code with root privileges. The flaw exists in the httpd service due to insufficient input validation when copying user-supplied data to a fixed buffer. Only users with TP-Link TL-WR940N routers running specific vulnerable firmware are affected.
💻 Affected Systems
- TP-Link TL-WR940N
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router with root-level code execution, allowing attackers to intercept all network traffic, modify DNS settings, install persistent malware, and pivot to other devices on the network.
Likely Case
Router takeover leading to man-in-the-middle attacks, credential theft from network traffic, and installation of backdoors for persistent access.
If Mitigated
Limited impact if proper network segmentation and access controls prevent adjacent attackers from reaching the router's management interface.
🎯 Exploit Status
Exploitation requires authentication credentials and network adjacency. The vulnerability is well-documented with technical details available from ZDI.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check TP-Link for latest firmware updates
Vendor Advisory: https://www.tp-link.com/us/support/download/tl-wr940n/
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to System Tools > Firmware Upgrade. 3. Download latest firmware from TP-Link website. 4. Upload and install firmware. 5. Router will reboot automatically.
🔧 Temporary Workarounds
Disable remote management
allPrevent access to router web interface from LAN/WLAN
Change default credentials
allUse strong, unique passwords for router admin access
🧯 If You Can't Patch
- Segment router management interface to restricted VLAN
- Implement network access controls to limit who can reach router management port 80
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface under System Tools > Firmware UpgradeCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Verify firmware version matches latest available from TP-Link website📡 Detection & Monitoring
Log Indicators:
- Multiple failed login attempts followed by successful login and unusual HTTP requests to router management interface
- Unusual process execution or memory corruption events in router logs
Network Indicators:
- Unusual HTTP POST requests to router port 80 with large payloads
- Traffic patterns suggesting buffer overflow exploitation
SIEM Query:
source="router_logs" AND (event="authentication_success" OR event="http_request") AND (uri CONTAINS "/cgi" OR data_size>1000)