CVE-2025-64210

Executive Summary

CVE-2025-64210 is a Missing Authorization vulnerability (CWE-862) in the Masterstudy Elementor Widgets WordPress plugin, developed by StylemixThemes. The flaw affects all versions up to and including 1.2.4. An unauthenticated attacker can exploit incorrectly configured access control security levels to perform unauthorized actions, such as modifying widget settings or accessing protected data. The vulnerability has a CVSS score of 5.4 (Medium), with a low attack complexity and no privileges required. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating a low probability of active exploitation in the wild.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem. The plugin is distributed via the official WordPress Plugin Directory and StylemixThemes' own channels. Users are advised to monitor for updates and consider disabling the plugin until a patch is available.

CVSS Breakdown & Threat Level

• CVSS Score: 5.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
• Attack Vector (AV): Network – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): None – No user action is required.
• Scope (S): Unchanged – The exploit does not affect other components.
• Confidentiality (C): Low – Limited information disclosure.
• Integrity (I): Low – Limited ability to modify data.
• Availability (A): None – No impact on system availability.

Threat Level: Medium. The lack of a public PoC and low EPSS score reduce immediate risk, but the unpatched status and ease of exploitation (no auth, low complexity) make it a potential target for automated scanning.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the masterstudy-elementor-widgets plugin. The plugin registers several AJAX actions and REST API endpoints that handle widget configuration, template loading, and data retrieval. These endpoints are intended to be accessible only to authenticated users with specific capabilities (e.g., edit_posts or manage_options). However, due to improper implementation, the plugin fails to verify user permissions before executing sensitive operations.

Root Cause: The plugin uses WordPress's wp_ajax_ and wp_ajax_nopriv_ hooks incorrectly. Some actions are registered with nopriv (allowing unauthenticated access) without proper capability checks. For example, an endpoint that loads widget settings might be accessible via wp_ajax_nopriv_masterstudy_load_widget, allowing any visitor to retrieve or modify widget data.

Attack Vector: An unauthenticated attacker sends crafted HTTP requests to the vulnerable endpoints. The attacker can:

• Retrieve sensitive widget configuration data (e.g., API keys, custom CSS/JS).
• Modify widget settings to inject malicious content (e.g., XSS payloads).
• Bypass access controls to perform actions reserved for administrators.

Impact: Successful exploitation can lead to information disclosure (e.g., API keys, internal paths) and limited integrity compromise (e.g., defacement, malicious redirects). Full site takeover is unlikely but possible if combined with other vulnerabilities.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on common fixes for missing authorization vulnerabilities.

Vulnerable Code (Example):

add_action('wp_ajax_nopriv_masterstudy_load_widget', 'masterstudy_load_widget_callback');
function masterstudy_load_widget_callback() {
    // No capability check
    $widget_id = $_POST['widget_id'];
    // Process request...
    wp_send_json_success($data);
}

Patched Code (Expected):

add_action('wp_ajax_masterstudy_load_widget', 'masterstudy_load_widget_callback');
// Remove nopriv action to require authentication
function masterstudy_load_widget_callback() {
    // Add capability check
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    $widget_id = $_POST['widget_id'];
    // Process request...
    wp_send_json_success($data);
}

Key Differences:

• The patched version removes the nopriv action, requiring authentication.
• A capability check (current_user_can('edit_posts')) is added before processing.
• Nonce verification should also be implemented to prevent CSRF.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A WordPress site with Masterstudy Elementor Widgets <= 1.2.4 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify Vulnerable Endpoints: Use a tool like Burp Suite or curl to enumerate AJAX actions. Look for patterns like wp-admin/admin-ajax.php?action=masterstudy_*.
2. Craft Request: Send a POST request to the vulnerable endpoint without authentication.

   curl -X POST http://target.com/wp-admin/admin-ajax.php \
        -d "action=masterstudy_load_widget&widget_id=1"
   

3. Extract Data: If the endpoint returns sensitive data (e.g., API keys), capture it.
4. Modify Settings: If the endpoint allows writes, inject malicious content.

   curl -X POST http://target.com/wp-admin/admin-ajax.php \
        -d "action=masterstudy_save_widget&widget_id=1&widget_data=<script>alert('XSS')</script>"
   

Note: No public exploit code is available. The above is a generic example.

Blue Team (Defensive)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with action parameters starting with masterstudy_ from unauthenticated users.
• Look for repeated requests to the same endpoint without a valid nonce or session cookie.

Mitigation:

• Disable the plugin until a patch is released.
• Implement a Web Application Firewall (WAF) rule to block requests to masterstudy_* actions from unauthenticated sources.
• Use a security plugin (e.g., Wordfence) to add virtual patching.

Lab Setup:

• Use a local WordPress installation (e.g., via Docker) with the vulnerable plugin.
• Install a debugging plugin (e.g., Query Monitor) to trace AJAX requests.
• Simulate attacks using curl or a Python script.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /wp-admin/admin-ajax.php with action=masterstudy_* parameters.
  • Unusual POST data containing widget IDs or configuration payloads.
• File IOCs:
  • Modified plugin files in /wp-content/plugins/masterstudy-elementor-widgets/.
  • Unexpected entries in WordPress options table (e.g., masterstudy_widget_data).
• Log IOCs:
  • Repeated 200 responses to admin-ajax.php from unauthenticated IPs.
  • Error logs showing "Unauthorized" or "403" for legitimate users.

Detection Engineering

YARA Rule

rule CVE_2025_64210_Masterstudy_Missing_Auth {
    meta:
        description = "Detects exploitation attempts for CVE-2025-64210 in Masterstudy Elementor Widgets"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-64210"
    strings:
        $ajax_action = /action=masterstudy_[a-z_]+/
        $nopriv = /wp_ajax_nopriv_masterstudy_/
        $widget_data = /widget_data=/
    condition:
        $ajax_action and ($nopriv or $widget_data)
}

Sigma Rule

title: CVE-2025-64210 Masterstudy Elementor Widgets Missing Authorization
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated AJAX requests to Masterstudy Elementor Widgets endpoints
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=masterstudy_'
    condition: selection
falsepositives:
    - Legitimate admin actions (requires authentication)
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-64210 Masterstudy Elementor Widgets Missing Authorization Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=masterstudy_"; http_client_body;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
    reference:cve,2025-64210;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Plugin: Deactivate and delete the Masterstudy Elementor Widgets plugin until a patch is released.
2. Virtual Patching: Use a WAF to block requests to admin-ajax.php with action=masterstudy_* from unauthenticated users.
3. Monitor Logs: Review web server and WordPress logs for suspicious AJAX activity.

Long-Term Fix:

• Apply the official patch once released by StylemixThemes.
• Update the plugin to the latest version (if patched).
• Implement principle of least privilege for all WordPress plugins.

Workaround:

• Add the following code to the theme's functions.php to block unauthenticated access:

  add_action('init', function() {
      if (defined('DOING_AJAX') && DOING_AJAX && !is_user_logged_in()) {
          $action = $_REQUEST['action'] ?? '';
          if (strpos($action, 'masterstudy_') === 0) {
              wp_die('Unauthorized', 403);
          }
      }
  });
  

Valters IT
Securing Digital Frontiers