CVE-2022-24355
📋 TL;DR
This vulnerability allows attackers on the same network to execute arbitrary code as root on TP-Link TL-WR940N routers without authentication. It's a stack-based buffer overflow in file name extension parsing that enables remote code execution. Only users of specific TP-Link router models with vulnerable firmware are affected.
💻 Affected Systems
- TP-Link TL-WR940N
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of router with root access, allowing attacker 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, and network surveillance.
If Mitigated
No impact if router is patched or isolated from untrusted networks.
🎯 Exploit Status
ZDI published advisory with technical details. No authentication required makes exploitation straightforward for network-adjacent attackers.
🛠️ 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 admin 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
Network Segmentation
allIsolate router from untrusted networks and limit access to management interface.
Disable Remote Management
allEnsure router management interface is only accessible from LAN, not WAN.
🧯 If You Can't Patch
- Replace router with supported model that receives security updates
- Implement strict network segmentation and firewall rules to limit router exposure
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Tools > Firmware UpgradeCheck Version:
Not applicable - check via web interfaceVerify Fix Applied:
Confirm firmware version is newer than 3.20.1 Build 200316 Rel.34392n (5553)📡 Detection & Monitoring
Log Indicators:
- Unusual file upload attempts to router management interface
- Multiple failed parsing attempts in router logs
Network Indicators:
- Unusual traffic patterns to router management port (typically 80/443)
- Buffer overflow attempts in HTTP requests
SIEM Query:
source="router_logs" AND ("buffer overflow" OR "parsing error" OR "malformed request")