CVE-2023-5357: Stored Cross-Site Scripting Vulnerability Found in Instagram for WordPress Plugin - Your Site Could Be at Risk!

Attention WordPress site owners! A critical vulnerability (CVE-2023-5357) has been identified in the popular "Instagram for WordPress" plugin (versions up to and including 2.1.6) that could leave your site exposed to malicious attacks. The vulnerability pertains to Stored Cross-Site Scripting (XSS), which allows authenticated attackers with contributor-level or higher permissions to inject arbitrary web scripts into pages. These injected scripts will execute whenever a user accesses the affected page, leading to various security risks such as unauthorized data access, manipulation, or even complete site takeover. Read on to learn more about this vulnerability and how you can protect your WordPress site.

Code Snippet

The vulnerability lies in the handling of shortcodes in the affected plugin. Insufficient input sanitization and output escaping on user-supplied attributes makes it possible for an attacker to inject malicious JavaScript code through these shortcodes. Here's a sample of the vulnerable code in the plugin:

function insta_shortcode_handler($atts) {
    $a = shortcode_atts( array(
        'username' => '',
        'style' => '',
        'link' => '',
    ), $atts );

    return insta_get_instagram_photos($a['username'], $a['style'], $a['link']);
}

As you can see, the shortcode_atts() function doesn't properly sanitize or escape the user-supplied attributes like username, style, or link, leaving room for attackers to insert malicious scripts.

Exploit Details

To exploit this vulnerability, an attacker would first need to have contributor-level or above privileges on your WordPress site. An affected site might start seeing unwanted behavior ranging from unauthorized data access to complete site takeover. Here's an example of the JavaScript code that an attacker might inject using the vulnerable shortcode:

[instagram username="attacker_username" style=""/><script>alert('XSS');</script>"]

After this exploit, whenever a user visits a page containing the maliciously injected scripts, they will see an alert box saying "XSS" – a sign that the injected script has executed. In the real world, attackers might use more subtle and sophisticated techniques to exploit the vulnerability without drawing attention, thereby maintaining the element of surprise.

Original References

1. Instagram for WordPress 2.1.6 - Stored Cross-Site Scripting (XSS)
2. CVE-2023-5357: Critical Stored XSS vulnerability in Instagram for WordPress plugin

How To Protect Your Site

The first and foremost step is to update your "Instagram for WordPress" plugin to the latest version. The developers have released version 2.1.7, which addresses the vulnerability by implementing proper input sanitization and output escaping. You can download the update from the WordPress plugin repository.

Additionally, it's always a good practice to limit the user privileges on your WordPress site, especially for those who might not fully understand the potential security risks of plugin vulnerabilities like this one.

Conclusion

Keeping your WordPress site safe from hackers and malicious attacks is an ongoing challenge. This Stored Cross-Site Scripting vulnerability found in the "Instagram for WordPress" plugin just highlights one of the many risks site owners face. By staying informed about the latest vulnerabilities and promptly updating your plugins and themes, you'll minimize the chances of your site becoming a victim of cyberattacks. Trust us, it’s worth taking the time and making the effort!

Timeline

Published on: 10/04/2023 02:15:10 UTC
Last modified on: 11/07/2023 04:23:56 UTC