CVE-2023-5817: Stored Cross-Site Scripting Vulnerability in Neon Text Plugin for WordPress Affecting all versions up to and including 1.1

WordPress, a widely-used CMS platform, powers millions of sites & blogs worldwide. Countless plugins facilitate these sites, by adding unique designs and functionality. One such popular plugin is Neon Text. It offers aesthetic value to WordPress themes, by adding a glowing text effect on pages. However, a recently discovered vulnerability, CVE-2023-5817, has been found to affect the plugin. This blog highlights this vulnerability in detail, its impact, and how to remediate this issue.

The Neon Text Plugin Vulnerability (CVE-2023-5817)

On all Neon Text plugin versions up to and including 1.1, a Stored Cross-Site Scripting (XSS) vulnerability exists. Specifically, the vulnerability lies in the plugin's 'neontext_box' shortcode. Insufficient input sanitization and output escaping on the user-supplied attribute (color) exposes systems to this XSS flaw. Consequently, authenticated attackers (having contributor-level permissions or higher) can inject arbitrary web script code into pages. The injected code triggers and executes when users access the specific compromised pages.

Below is the vulnerable code snippet from the Neon Text Plugin's version 1.1

function neontext_box_shortcode($atts){
    $atts = shortcode_atts(array(
        'color' => 'lightblue',
    ), $atts, 'neontext_box');

    $output = '<div class="neontext-box" style="color: '.$atts['color'].';">';
    return $output;
}
add_shortcode( 'neontext_box', 'neontext_box_shortcode' );

As demonstrated above, the neontext_box_shortcode function receives user attributes [such as 'color'] without proper sanitization and then uses it to build a CSS color style. Because no escaping or validation is performed, an attacker can abuse this functionality to inject malicious scripts.

Exploit Details

To exploit this Stored XSS vulnerability, an attacker requires contributor-level permissions or above on a WordPress site. On successfully authenticating and gaining these permissions, the attacker creates a new post, or edits an existing one, and inserts a malicious shortcode like this:

[neontext_box color="red;"><script>alert('XSS')</script>"]

This embedded malicious script loads and executes whenever a user accesses the affected pages. Consequently, it threatens the confidentiality and integrity of user data, potentially causing considerable harm to the site's visitors and the site itself.

For further reading & original references, refer to these links

- CVE-2023-5817 - National Vulnerability Database (NVD)
- WordPress Neon Text Plugin Vulnerability Details - WPVulnDB

To address the Neon Text Plugin vulnerability, perform these steps

- Update the Neon Text plugin to the latest available version (ensure it has resolved the vulnerability).

Utilize a Web Application Firewall (WAF) to inspect and block suspicious requests & payloads.

- Conduct security audits and vulnerabilities scanning regularly. Stay up to date on security updates, advisories, and patches.

Conclusion

Understanding and mitigating vulnerabilities like CVE-2023-5817 in the Neon Text plugin is vital to protecting your WordPress site from potential attacks and breaches. Stay informed, frequently update plugins, and employ security measures to ensure your site's integrity and safety.

Timeline

Published on: 10/27/2023 11:15:13 UTC
Last modified on: 11/07/2023 21:16:59 UTC