CVE-2021-24243 : Security Advisory and Response

Webmasters should be aware of a stored Cross-Site Scripting (XSS) vulnerability in the WPBakery Page Builder (Visual Composer) Clipboard WordPress plugin version 4.5.6 and below. This flaw allows low privilege users to inject malicious code that gets triggered across all backend pages.

Understanding CVE-2021-24243

This CVE involves a lack of capability checks and sanitization in an AJAX action registered by the WPBakery Page Builder Clipboard plugin before version 4.5.6, enabling users with subscriber+ permissions to exploit the vulnerability.

What is CVE-2021-24243?

An AJAX action in WPBakery Page Builder Clipboard plugin < 4.5.6 lacked capability checks, permitting low privilege users to inject XSS payloads, causing unauthorized code execution on backend pages.

The Impact of CVE-2021-24243

The vulnerability exposes websites to stored XSS attacks, allowing unauthorized users to inject malicious scripts leading to various security risks such as data theft, unauthorized actions, and website defacement.

Technical Details of CVE-2021-24243

This section includes detailed information on the vulnerability, affected systems, and how the exploit works.

Vulnerability Description

The flaw in WPBakery Page Builder Clipboard plugin versions < 4.5.6 enables low privilege users to inject XSS payloads into an AJAX action without proper validation, leading to unauthorized code execution in backend pages.

Affected Systems and Versions

WPBakery Page Builder (Visual Composer) Clipboard plugin versions before 4.5.6 are impacted by this vulnerability, allowing attackers with subscriber+ permissions to exploit the flaw.

Exploitation Mechanism

By leveraging the lack of capability checks and sanitization in the vulnerable plugin, low privilege users can inject malicious XSS payloads through an AJAX action, triggering unauthorized code execution.

Mitigation and Prevention

To safeguard websites from potential XSS attacks, immediate actions and long-term security practices need to be implemented.

Immediate Steps to Take

Webmasters should update the WPBakery Page Builder Clipboard plugin to version 4.5.6 or above, restrict access to low privilege users, and sanitize user inputs to prevent XSS injection.

Long-Term Security Practices

Regularly monitor and update plugins, conduct security audits, educate users on safe practices, and implement strict access controls to mitigate XSS vulnerabilities.

Patching and Updates

Ensuring timely installation of security patches and updates provided by plugin vendors is crucial in addressing known vulnerabilities and enhancing website security.