CVE-2024-37922

Executive Summary

CVE-2024-37922 is a stored Cross-Site Scripting (XSS) vulnerability in the Premium Addons for Elementor WordPress plugin, affecting versions up to and including 4.10.34. The vulnerability arises from improper neutralization of user-supplied input during web page generation, allowing an authenticated attacker with contributor-level access or higher to inject arbitrary JavaScript into widget settings. When an administrator or other user views a page containing the malicious widget, the injected script executes in their browser session, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is part of the WordPress ecosystem and is not related to Apache or Nginx. The CVSS score of 6.5 (Medium) reflects the need for authenticated access and user interaction, but the impact is amplified in multi-role WordPress environments. No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch.

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 dashboard or manual upload are at risk. No supply chain compromise has been reported, but the lack of a patch means all installations of the affected versions are vulnerable.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The attack is carried out over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – The attacker must be authenticated as a contributor or higher.
• User Interaction (UI): Required (R) – The victim must view the compromised page.
• Scope (S): Changed (C) – The vulnerability impacts resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify content.
• Availability (A): Low (L) – Limited impact on availability.

Threat Level: Medium. The requirement for authenticated access reduces the attack surface, but the potential for privilege escalation and lateral movement in a WordPress environment makes this a significant risk for sites with multiple user roles.

Deep Dive & Mechanics

The vulnerability exists in the widget rendering logic of the Premium Addons for Elementor plugin. The plugin fails to sanitize or escape user-supplied input when generating HTML output for certain widget parameters. An attacker with contributor-level access can create or edit a post/page using Elementor and insert a vulnerable widget (e.g., a testimonial, pricing table, or team member widget). By injecting a malicious payload into a text field (such as a name, description, or URL), the payload is stored in the database and later rendered without proper escaping.

When an administrator or other user views the page, the injected JavaScript executes in their browser context. This can be used to steal cookies, perform actions on behalf of the victim, or redirect to malicious sites.

Root Cause: The plugin uses echo or print functions without applying WordPress escaping functions like esc_html(), esc_attr(), or wp_kses_post() on user-controlled data.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on common XSS fixes.

Vulnerable Code (pre-4.10.34):

// In a widget render method
$title = $settings['title'];
echo '<h3 class="premium-title">' . $title . '</h3>';

Patched Code (hypothetical):

// In a widget render method
$title = $settings['title'];
echo '<h3 class="premium-title">' . esc_html( $title ) . '</h3>';

The patched version uses esc_html() to neutralize any HTML or JavaScript before output.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress installation with Premium Addons for Elementor <= 4.10.34.
• A user account with contributor-level access or higher.

Exploitation Steps:

1. Log in as a contributor.
2. Create a new post or page using Elementor.
3. Add a vulnerable widget (e.g., "Testimonial" or "Pricing Table").
4. In a text field (e.g., "Name" or "Description"), inject the following payload:

   <img src=x onerror=alert('XSS')>
   

5. Save and publish the post.
6. As an administrator, view the published post. The JavaScript executes.

Advanced Payload:

<script>
fetch('/wp-admin/admin-ajax.php?action=your_malicious_action');
</script>

Blue Team

Detection:

• Monitor for unusual widget content in posts/pages.
• Look for HTML tags or JavaScript in fields that should only contain plain text.
• Use the detection rules provided below.

Mitigation:

• Immediately restrict contributor-level access if possible.
• Apply a Web Application Firewall (WAF) rule to block common XSS patterns.
• Monitor logs for suspicious AJAX requests originating from Elementor widgets.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available; plugin files are standard WordPress plugin files)
• Network Indicators:
  • Outbound connections to attacker-controlled domains from the WordPress admin panel.
  • Unusual AJAX requests to /wp-admin/admin-ajax.php with suspicious parameters.
• Log Entries:
  • WordPress debug log entries showing unescaped output.
  • Web server logs with requests containing <script> tags in POST data.
• Database Indicators:
  • Rows in wp_postmeta or wp_posts containing HTML/JavaScript in fields that should be plain text.

Detection Engineering

YARA Rule

rule Detect_Premium_Addons_XSS_Payload {
    meta:
        description = "Detects XSS payloads targeting Premium Addons for Elementor"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-37922"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"']*["']?/i
        $xss3 = /onload\s*=\s*["']?[^"']*["']?/i
    condition:
        any of ($xss*) and filesize < 10KB
}

Sigma Rule

title: Potential XSS via Premium Addons for Elementor
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects XSS payloads in POST requests to WordPress admin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=elementor'
        sc-status: 200
    keywords:
        - '<script'
        - 'onerror='
        - 'onload='
    condition: selection and keywords
falsepositives:
    - Legitimate use of JavaScript in Elementor widgets (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-37922 Premium Addons XSS Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=elementor"; http_uri; pcre:"/(<script|onerror=|onload=)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if it is not critical to operations.
2. Restrict user roles – Only grant contributor access to trusted users.
3. Apply a WAF rule to block common XSS patterns in POST data.

Long-Term Fix:

• Monitor the vendor's website for a patched version (expected to be 4.10.35 or higher).
• Once a patch is released, update immediately.
• Consider using a security plugin (e.g., Wordfence) to add an additional layer of protection.

Workaround:

• If the plugin cannot be disabled, manually audit all widgets and apply esc_html() or wp_kses_post() to any user-controlled output. This requires modifying plugin files and will be overwritten on update.

Valters IT
DevSecOps & Cyber Threat Intelligence