CVE-2024-6307 - WordPress Core Vulnerability to Stored Cross-Site Scripting: Insights, Exploits, and Remediation Steps

The Common Vulnerabilities and Exposures (CVE) project provides a public database of known security vulnerabilities in software and systems. CVE-2024-6307 is an identified vulnerability in WordPress Core, affecting versions prior to 6.5.5. The vulnerability is a Stored Cross-Site Scripting (XSS) flaw that stems from insufficient input sanitization and output escaping on URLs. When exploited, this vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts into pages, which execute as users access these injected pages.

In this post, we'll dive deep into the details of CVE-2024-6307, discuss code snippets demonstrating the exploit, share links to original references, and provide guidance for remediation.

Vulnerability Details

WordPress is an open-source content management system (CMS) that allows users to create and manage websites without extensive programming knowledge. The WordPress Core is the main software that powers the CMS and its various plugins and themes.

The vulnerability, CVE-2024-6307, affects the HTML API of the WordPress Core. This API is responsible for handling various aspects of HTML content on a WordPress website, including the creation of URLs, images, and other HTML elements.

Exploit Details

By exploiting CVE-2024-6307, an attacker with contributor-level access or higher can inject arbitrary JavaScript code into a WordPress post or page. This injected code will then execute in the context of the visitor's browser, potentially allowing the attacker to steal sensitive information, force actions on the visitor's behalf, deface a website, or other harmful actions.

Here's an example code snippet demonstrating a flawed sanitization process in the WordPress Core and how an attacker can misuse it to inject malicious script:

// Flawed Sanitization Example
function create_custom_link($url, $link_text) {
  $sanitized_url = esc_url($url);

  return '<a href="' . $sanitized_url . '">' . $link_text . '</a>';
}

//Malicious Script Injection Example
$attacker_url = "javascript:alert('XSS!');";
$injected_link = create_custom_link($attacker_url, "Click Me");
echo $injected_link;

In this example, the function create_custom_link() attempts to sanitize the provided URL by using the esc_url() function. However, it fails to prevent the use of the "javascript" scheme, enabling an attacker to inject a malicious script via the $attacker_url variable.

Original References

- WordPress Core CVE-2024-6307 vulnerability details: https://wpvulndb.com/vulnerabilities/11050
- Example of a Stored XSS Attack: https://owasp.org/www-project-web-security-testing-guide/latest/4-Web_Application_Security_Testing/07-Input_Validation_Testing/20-Testing_for_Stored_Cross_Site_Scripting

Remediation Steps

To mitigate the risk of CVE-2024-6307 vulnerability, WordPress administrators should take the following steps:

1. Update WordPress Core to the latest version (6.5.5+) to apply security patches that address this vulnerability.
2. Regularly review user roles and permissions on the website, ensuring that contributor-level and higher access is limited to trusted individuals.
3. Install security plugins, such as Wordfence or Sucuri, to help monitor and protect the WordPress website against potential attacks.
4. Implement a Content Security Policy (CSP) on the website to restrict the execution of JavaScript from untrusted sources.

Conclusion

CVE-2024-6307 is a critical vulnerability in WordPress Core, affecting various versions prior to 6.5.5. As a website administrator or developer, it's essential to keep your WordPress installation updated to ensure protection against this Stored XSS exploit. By following the remediation steps outlined in this post and staying informed about software updates and emerging threats, you can maintain a secure and reliable website for your users.

Timeline

Published on: 06/25/2024 11:15:50 UTC
Last modified on: 07/06/2024 03:10:01 UTC