CVE-2025-0393

Executive Summary

CVE-2025-0393 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Royal Elementor Addons and Templates plugin for WordPress, affecting all versions up to and including 1.7.1006. The flaw resides in the wpr_filter_grid_posts() function, which lacks proper nonce validation. This allows an unauthenticated attacker to forge requests that, when triggered by a logged-in administrator (e.g., via a malicious link), can inject arbitrary web scripts. Successful exploitation could lead to stored XSS, enabling the attacker to execute malicious actions within the admin context, such as modifying site content, creating rogue admin accounts, or exfiltrating sensitive data.

As a WordPress plugin vulnerability, this issue is confined to the WordPress ecosystem and does not involve server-level components like Apache or Nginx. The plugin is widely used for building dynamic content grids, making this a high-impact vector for site compromise.

Supply Chain & Package Security

This vulnerability is specific to the Royal Elementor Addons and Templates WordPress plugin. While not a traditional package manager (NPM, PyPI, etc.) issue, the plugin is distributed via the WordPress plugin repository and third-party marketplaces. Users should verify the integrity of their plugin files and ensure they are sourced from official channels. The lack of a patch from the vendor increases supply chain risk, as administrators must rely on manual mitigations.

CVSS Breakdown & Threat Level

• CVSS Score: 6.1 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
• Attack Vector (AV): Network – Exploitable remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): None – No authentication needed for the attacker.
• User Interaction (UI): Required – Victim must click a link or visit a crafted page.
• Scope (S): Unchanged – The vulnerable component remains the same.
• Confidentiality (C): High – Potential for data exfiltration.
• Integrity (I): High – Ability to modify site content or settings.
• Availability (A): None – No direct impact on availability.

Threat Level: Medium. The requirement for user interaction reduces the immediate risk, but the potential for full administrative compromise makes this a serious concern for WordPress sites using the plugin.

Deep Dive & Mechanics

The vulnerability is a classic CSRF in the WordPress plugin's AJAX handler. The wpr_filter_grid_posts() function is intended to filter and return posts for dynamic grids. However, it fails to verify a nonce (a one-time token) before processing the request. In WordPress, nonces are used to ensure that requests originate from the intended user and not from a third-party site.

An attacker can craft a malicious HTML page or email containing a form or image tag that submits a POST request to the vulnerable endpoint. If an authenticated administrator visits this page, the browser automatically sends the request with the admin's cookies. The lack of nonce validation means the request is processed as if it came from the admin.

The injected web script (e.g., JavaScript) can then be stored in the WordPress database (e.g., via a post or comment) or executed immediately. This can lead to:

• Stored XSS: Malicious scripts persist and execute for other users.
• Privilege Escalation: Creating new admin users.
• Data Theft: Stealing session cookies or sensitive information.

Vulnerable vs. Patched Code

Vulnerable Code (<= 1.7.1006): The wpr_filter_grid_posts() function likely lacks a nonce check. A simplified representation:

add_action('wp_ajax_wpr_filter_grid_posts', 'wpr_filter_grid_posts');
function wpr_filter_grid_posts() {
    // No nonce verification
    $post_data = $_POST;
    // Process and return filtered posts
    echo json_encode($result);
    wp_die();
}

Patched Code (Hypothetical): A secure version would include a nonce check:

add_action('wp_ajax_wpr_filter_grid_posts', 'wpr_filter_grid_posts');
function wpr_filter_grid_posts() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'wpr_filter_grid_nonce')) {
        wp_die('Security check failed.');
    }
    $post_data = $_POST;
    // Process and return filtered posts
    echo json_encode($result);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site with Royal Elementor Addons <= 1.7.1006 installed.
• An authenticated administrator session.

Exploit Steps:

1. Craft a Malicious Request: Create an HTML page that submits a POST request to the vulnerable endpoint with a payload.
2. Host the Page: Place the HTML on an attacker-controlled server or use a phishing email.
3. Trick the Admin: Send the link to the admin and convince them to click it.
4. Execute Payload: The forged request injects a script that creates a new admin user.

Example Malicious HTML:

<html>
<body>
<form action="http://target-site.com/wp-admin/admin-ajax.php" method="POST" id="csrf_form">
    <input type="hidden" name="action" value="wpr_filter_grid_posts">
    <input type="hidden" name="data" value="<script>alert('XSS')</script>">
</form>
<script>document.getElementById('csrf_form').submit();</script>
</body>
</html>

Note: No public exploit code is available from Exploit-DB at this time.

Blue Team (Defense & Detection)

Detection:

• Monitor for unusual POST requests to /wp-admin/admin-ajax.php with action=wpr_filter_grid_posts.
• Look for unexpected changes in user roles or new admin accounts.
• Use Web Application Firewall (WAF) rules to block requests missing nonce parameters.

Mitigation:

• Disable the plugin until a patch is released.
• Implement a WAF rule to require nonce validation for all AJAX actions.
• Educate administrators about phishing risks.

Indicators of Compromise (IOCs)

• Network:
  • POST requests to /wp-admin/admin-ajax.php with action=wpr_filter_grid_posts and no _wpnonce parameter.
  • Outbound connections to attacker-controlled IPs after script execution.
• Host:
  • Unexpected admin users in the WordPress database (wp_users table).
  • Modified or new posts containing <script> tags.
  • Plugin file modifications (e.g., royal-elementor-addons/ directory).
• Logs:
  • WordPress debug logs showing failed nonce checks (if patched).
  • Web server logs with unusual referrer headers.

Detection Engineering

YARA Rule

rule CVE_2025_0393_CSRF_WordPress {
    meta:
        description = "Detects malicious requests targeting CVE-2025-0393 in Royal Elementor Addons"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-0393"
    strings:
        $ajax_action = "wpr_filter_grid_posts"
        $nonce_missing = "wp_verify_nonce" nocase
    condition:
        $ajax_action and not $nonce_missing
}

Sigma Rule

title: CVE-2025-0393 CSRF Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects POST requests to WordPress admin-ajax.php with the vulnerable action
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=wpr_filter_grid_posts
    condition: selection
falsepositives:
    - Legitimate plugin usage (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-0393 CSRF Attempt - Royal Elementor Addons";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"admin-ajax.php"; http_uri;
    content:"action=wpr_filter_grid_posts"; http_client_body;
    sid:1000001;
    rev:1;
    reference:cve,2025-0393;
    classtype:web-application-attack;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Plugin: Deactivate and remove the Royal Elementor Addons plugin until a patch is released.
2. Apply Virtual Patching: Use a WAF to block requests to admin-ajax.php that lack a valid nonce for the vulnerable action.
3. Audit User Accounts: Check for unauthorized admin accounts and remove them.
4. Review Logs: Examine web server and WordPress logs for signs of exploitation.

Long-Term Measures:

• Monitor the vendor's website for a patched version (>= 1.7.1007).
• Implement Content Security Policy (CSP) headers to mitigate XSS.
• Enforce strong nonce validation in all custom WordPress plugins.
• Conduct regular security training for administrators.

Workaround: If the plugin cannot be disabled, add the following code to the theme's functions.php to enforce nonce validation:

add_action('wp_ajax_wpr_filter_grid_posts', function() {
    if (!wp_verify_nonce($_REQUEST['_wpnonce'], 'wpr_filter_grid_nonce')) {
        wp_die('CSRF detected.');
    }
}, 1);

Valters IT
Securing Digital Frontiers