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In June 2024, a new critical vulnerability, CVE-2024-54126, has been identified in TP-Link's popular Archer C50 wireless router. Security researchers have confirmed this bug allows attackers to upload and run malicious firmware due to weak signature verification during the web-based firmware upgrade process. Let’s break down what’s going on, how this can be attacked, and what you can do about it.
What Is CVE-2024-54126?
The Archer C50 is a widely used Wi-Fi router in many homes and small businesses. To keep the router safe and add new features, device owners can use the web admin interface to upload new firmware updates.
But here’s the problem: TP-Link’s firmware check is flawed. The system fails to properly verify the digital signature of uploaded firmware files. That means a logged-in administrator (or someone who has the admin password) and is within Wi-Fi range, can upload a malicious firmware file and completely take over the router.
Attacker connects to the router's Wi-Fi network.
2. Logs into the admin web interface (http://192.168..1 by default).
Where the Verification Breaks
Let’s look at where things break down. Here’s a simplified pseudocode of the firmware upgrade function (based on public PoCs and router firmware analysis):
function handleFirmwareUpload(uploadedFile):
// Extract signature from uploaded firmware
signature = extractSignature(uploadedFile)
// Supposed to validate signature
if (validateSignature(signature, uploadedFile) == TRUE):
installFirmware(uploadedFile)
else:
rejectUpload("Invalid signature!")
The issue: In TP-Link’s implementation, either validateSignature() is faulty (always returns TRUE), or the check is skipped for certain uploads. Firmware files with a valid structure but a bogus or test signature are accepted as genuine.
Prepare a Custom Firmware:
Use open-source tools (e.g., binwalk) to unpack a stock firmware. Inject a backdoor or custom script.
Go to firmware upgrade page in browser, pick your tampered binary, and upload.
Persistent Backdoor: Even after reboot, the attack stays unless the firmware is reflashed.
- Spread to Other Devices: The compromised router can launch attacks on devices within the network.
Mitigation and Recommendations
- Update your router: Check TP-Link’s official support page for Archer C50 and update to the latest firmware as soon as a patch is available.
Change Default Passwords: Always set a strong admin password.
Additional Resources
- Original CVE Record
- OpenWrt’s Archer C50 Page (for secure custom firmware)
- Router Security Checklist
Final Thoughts
CVE-2024-54126 is a serious reminder that even basic features like firmware upgrades require robust security. If you have a TP-Link Archer C50, don’t wait—update your firmware, harden your admin interface, and watch for vendor patches! If you’re curious about how signatures are handled in embedded devices, check out Binwalk’s guide to firmware analysis.
Stay safe, and make sure your home network isn’t the weak link.
*(This write-up is based on public sources and white hat research for educational purposes. Test only on devices you own and have permission to examine.)*
Timeline
Published on: 12/05/2024 13:15:09 UTC