In this blog post, we'll be discussing a recently disclosed vulnerability (CVE-2022-3374) in the Ocean Extra WordPress plugin - a popular add-on that extends the functionality of the OceanWP theme. This vulnerability, which affects versions of the plugin prior to 2..5, is related to an unsafe unserialization procedure that could lead to PHP object injection issues when a high privilege user imports a malicious Customizer Styling file.

We'll start by providing some background information on PHP object injection and the Ocean Extra plugin, and then we'll dive into the details of the exploit, including some code snippets for demonstration. We'll also cover the steps needed to mitigate the vulnerability, and we'll include links to the original references and resources.

Background

PHP object injection is a type of vulnerability that occurs when user input can be used to unserialize an arbitrary object into the application's context. This can potentially allow attackers to execute arbitrary PHP code or manipulate the application in unintended ways.

The Ocean Extra WordPress plugin allows users to import Customizer Styling files, which can be used to modify the appearance of their website through the OceanWP theme. This process should be controlled and executed safely, but the vulnerability covered in this post shows that the plugin fails to adequately protect against PHP object injection attacks in this context.

Exploit details

When a user imports a Customizer Styling file using the Ocean Extra plugin, the contents of the file are passed through the unserialize() function, which potentially allows an attacker to inject malicious PHP objects into the application. Here's a simplified code snippet demonstrating this vulnerability:

// Ocean Extra plugin import functionality (simplified for demonstration)
function import_customizer_styling_file( $file_content ) {
    // Vulnerable unserialize() call
    $unserialized_data = unserialize( $file_content );
    // Process unserialized data (apply styling changes, etc.)
}

And here's an example of a malicious Customizer Styling file containing a PHP object that could exploit this vulnerability:

O:8:"Malicious":1:{s:4:"code";s:53:"<?php echo 'This website has been compromised.'; ?>";}

If a high privilege user imports such a Customizer Styling file (either intentionally or unintentionally), this could result in PHP object injections when there is at least one suitable gadget chain present on the blog that is compatible with the injected object.

To avoid this vulnerability, you should

1. Update the Ocean Extra WordPress plugin to version 2..5 or later. The developers have fixed this issue in the latest release by adding security measures to the import functionality.
2. Only import Customizer Styling files from trusted sources. Even with mitigation efforts in place, it's always recommended to be cautious about the files you're importing into your website.
3. Regularly update all WordPress plugins, themes, and core files to ensure you're protected against known vulnerabilities.

References and Resources

For more information on this vulnerability and the Ocean Extra plugin, refer to the following resources:

- CVE-2022-3374 - Original vulnerability disclosure
- OceanWP Changelog - Details on the fixed version of the Ocean Extra plugin
- Mitigating PHP Object Injection - OWASP guidelines for properly mitigating PHP object injection vulnerabilities in general

Conclusion

In this post, we've examined the PHP object injection vulnerability in the Ocean Extra WordPress plugin (CVE-2022-3374) and provided a detailed explanation of the exploit. By following the mitigation steps outlined above, you can ensure that your WordPress website remains secure against this type of attack. It's critical to keep your plugins, themes, and core files up to date to safeguard your website from emerging threats.

Timeline

Published on: 10/31/2022 16:15:00 UTC
Last modified on: 11/01/2022 13:50:00 UTC