The popular UserPro plugin for WordPress is facing a critical vulnerability due to Cross-Site Request Forgery (CSRF) in versions up to, and including, 5.1.1. Thousands of WordPress websites are using UserPro to enhance user registration and management. This vulnerability allows unauthenticated attackers to modify the role of verified users and elevate their privileges to that of any user, including 'administrator', via a forged request. The attackers simply need to trick a site administrator into performing an action like clicking on a malicious link.

Vulnerability Details

The UserPro plugin for WordPress is found to be missing nonce validation within the 'admin_page', 'userpro_verify_user', and 'verifyUnverifyAllUsers' functions, making it susceptible to CSRF attacks. The lack of proper validation means that an attacker can potentially forge requests and escalate the privileges of a verified user on the website. This can lead to unauthorized access and manipulation of sensitive site data, which can be disastrous for the site owner and the users.

Code Snippet (Exploitable Functions)

Below is a code snippet that demonstrates the missing nonce validation in the exploitable functions.

function admin_page(){
  if ( (isset($_GET['role']) && $_GET['role']) && (isset($_GET['user_id']) && $_GET['user_id'])){
    $user = new WP_User( $_GET['user_id'] );
    $user->set_role( $_GET['role'] );

function userpro_verify_user(){
  // Missing nonce check
  $user_id = $_GET['user_id'];
  update_user_meta($user_id, '_userpro_verified', 1);

function verifyUnverifyAllUsers() {
  // Missing nonce check
  // Get all users
  $users = get_users( );
  foreach ( $users as $user ) {
    update_user_meta($user->ID, '_userpro_verified', 1);

Exploit Scenario

Suppose an attacker is aware of this vulnerability and aims to exploit it. They can craft a malicious link with the desired parameters to modify a verified user's role to 'administrator'. The attacker would then trick a site administrator into clicking the link, often through social engineering tactics, such as sending a phishing email or embedding the link on websites frequented by the administrator. Once the forged request is executed by the site administrator, the attacker's desired user account would be granted elevated privileges, allowing unauthorized access to critical site resources.

Mitigation and Recommendations

The developers of the UserPro plugin have been made aware of this issue, and it is strongly advised to update to the latest version of the plugin as soon as a patch becomes available. For users who are unable to immediately update, some temporary measures can be taken:

- Double-check the validity of suspicious email links and avoid opening them until you have verified their authenticity.
- Implement additional security measures, such as two-factor authentication (2FA), to minimize the risk of unauthorized access.
- Regularly monitor activity logs and user permissions to detect any unauthorized changes in user roles and privileges.

Original References

- CVE ID: CVE-2023-2440 (The CVE identifier for this vulnerability)
- Exploit Database: CVE-2023-2440 - UserPro Plugin for WordPress (Detailed analysis, proof-of-concept, and exploit information)

In conclusion, due to the nature of the vulnerability (CVE-2023-2440) in the UserPro plugin for WordPress, it is crucial that users update their plugin as soon as possible to minimize the risk of exploitation. Additionally, employing best security practices, such as 2FA and monitoring logs, can help thwart potential unauthorized access and safeguard your website.


Published on: 11/22/2023 16:15:00 UTC
Last modified on: 12/01/2023 16:11:00 UTC