CVE-2022-3357 - PHP Object Injection Vulnerability in Smart Slider 3 WordPress Plugin Prior to Version 3.5.1.11

The Smart Slider 3 WordPress plugin is widely used for creating customizable, responsive sliders and blocks for websites. A critical vulnerability (CVE-2022-3357) has been discovered that affects all versions of the plugin before 3.5.1.11. This could allow an attacker to perform PHP object injection attacks through the import functionality, potentially leading to severe consequences such as information disclosure, manipulation of server-side files, or even remote code execution.

More specifically, the vulnerability stems from the insecure handling of the content of an imported file. When a user imports a file (either intentionally or unintentionally), the plugin may unserialize the data in the file, putting the website at risk of a PHP object injection if a suitable gadget chain exists. In this post, we'll outline the exploit details, provide code snippets, and link to original references.

Exploit Details

The vulnerability arises due to the improper implementation of the unserialize() function within the import functionality code. Even when a user imports a malicious file designed to exploit the PHP object injection vulnerability, the intended security mechanisms do not mitigate the risk.

Here is a code snippet from the vulnerable code

public function importSlider($file) {
  //...
  $data = file_get_contents($file);
  //...
  $sliderData = unserialize(base64_decode($data));

In the above snippet, $data refers to the content of the imported file, and unserialize() method is applied to it after a base64 decoding. This process allows the formation of serialized malicious objects, which may trigger a suitable gadget chain present on the website for further exploitation.

Mitigation

To protect your website from this vulnerability, make sure you are using the Smart Slider 3 WordPress plugin version 3.5.1.11 or later. In the patched version, the developer has added a proper secure mechanism to handle the import functionality, mitigating the risk of PHP object injections. Update your plugin as soon as possible to avoid any potential attacks.

The vulnerability was responsibly disclosed, and further details can be found in these links

1. CVE-2022-3357 Official CVE Details
2. Smart Slider 3 WordPress Plugin Changelog

Conclusion

The CVE-2022-3357 vulnerability demonstrates the importance of secure coding practices and the need for diligent security reviews when developing plugins for popular content management systems like WordPress. As an end user, ensure that you keep your plugins up-to-date and implement proper validation and sanitation mechanisms to reduce the likelihood of security issues. With these measures in place, you can significantly reduce the attack surface and keep your website safer.

Timeline

Published on: 10/31/2022 16:15:00 UTC
Last modified on: 12/07/2022 02:16:00 UTC