Recently, the popular LayerSlider WordPress plugin, which is used to create stunning sliders and displays for a wide range of applications, was found to have a critical vulnerability: a Stored Cross-Site Scripting (XSS) attack. Identified as CVE-2024-4575, this vulnerability affects LayerSlider version 7.11. and is caused by insufficient input sanitization and output escaping on user-supplied attributes. As a result, authenticated attackers with contributor-level access or higher can inject malicious scripts into pages, causing a potential security risk every time a user accesses these pages.

Background and Vulnerability Details

LayerSlider for WordPress is a plugin that allows easy creation and management of sliders, carousels, galleries, and more on WordPress sites. As part of its functionality, the plugin includes the "ls_search_form" shortcode, which is designed to display a search form on the front end of the website. However, the 7.11. version of the plugin contains a critical vulnerability due to failing to properly sanitize user inputs and escape output for the shortcode attributes.

The vulnerability specifically exists in the plugin's handling of the ls_placeholders attribute. By submitting a specially crafted value for this attribute, an attacker with contributor-level access or higher can successfully inject a malicious script as part of the search form.

Here's an example of the vulnerable shortcode

[ls_search_form ls_placeholders="An=<img src=x onerror=alert(1)>y"]

In this case, the attacker injects an HTML image tag with a non-existent source ('x') and an "onerror" event handler that executes a simple JavaScript alert. When a user accesses a page containing this injected code, the alert would pop up, demonstrating an XSS attack.

Exploit Steps

1. Attacker gains contributor-level access or higher to a WordPress site using the LayerSlider plugin version 7.11.
2. Attacker creates a new post or edits an existing one and inserts the malicious shortcode containing their desired script.
3. When a user visits the affected page, the injected script executes within the user's browser, potentially compromising their session or exposing them to other security threats.

Mitigation and Recommendations

To protect your WordPress site from being exploited through CVE-2024-4575, the following steps are recommended:

- Update LayerSlider: The plugin developers have released a patch for this vulnerability in the form of LayerSlider version 7.11.1. Update your plugin as soon as possible to benefit from this security fix.
- Keep plugins up-to-date: Regularly updating all WordPress plugins helps to minimize the risk of known vulnerabilities being exploited on your site.
- Implement security best practices: Utilize a security plugin (such as Wordfence or Sucuri) to enhance your site's overall security posture. Ensure that strong password policies are in place, and limit administrative access to only the necessary personnel.

Original References

- CVE-2024-4575 Record
- LayerSlider Changelog

Conclusion

Stored Cross-Site Scripting vulnerabilities are serious and can lead to significant risks for both users and administrators of affected sites. It is essential to stay informed of these types of security flaws, and to actively maintain an up-to-date software environment. By applying the recommendations listed here and remaining vigilant about potential security threats, you can help protect your WordPress site against CVE-2024-4575 and other similar vulnerabilities.

Timeline

Published on: 05/23/2024 11:15:24 UTC
Last modified on: 06/04/2024 17:56:16 UTC