CVE-2022-37421 - Silverstripe CMS 4.11. XSS Vulnerability Exploitation

Silverstripe CMS, a widely used open-source content management system, is susceptible to a Cross-Site Scripting (XSS) vulnerability in versions up to and including 4.11.. This vulnerability, identified as CVE-2022-37421, allows an attacker to inject malicious code into a web page, potentially leading to unauthorized access to sensitive information, alteration of website content, or further attacks on website users.

In this post, we will examine the details of this vulnerability, the consequences of a successful exploit, and the steps website administrators should take to mitigate the risk. We will also share code snippets and references to original sources to facilitate your understanding and mitigation efforts.

Vulnerability Details

Cross-Site Scripting (XSS) vulnerabilities can be exploited when user input is not properly sanitized and displayed on a webpage. In the case of Silverstripe CMS 4.11. and earlier versions, the flaw stems from insufficient output encoding applied to the CMS's components, allowing an attacker to inject malicious JavaScript code through various input areas susceptible to XSS attacks.

Here's an example of malicious JavaScript code that may be injected

<script>alert('XSS Vulnerability')</script>

When other users visit a page containing this malicious code, the JavaScript will be executed in their browser, potentially causing data exfiltration, session hijacking, or other attacks.

Original References

The vulnerability was initially reported by a researcher and can be found in the following public sources:

1. Silverstripe CMS GitHub Repository: https://github.com/silverstripe/silverstripe-cms
2. CVE Details Page: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-37421
3. Silverstripe CMS Security Advisory: https://www.silverstripe.org/download/security-releases

Exploit Details

To exploit this vulnerability, an attacker must identify vulnerable input areas within a Silverstripe CMS and inject malicious JavaScript code.

Suppose a Silverstripe CMS website contains a user input form, such as a search box or comment field. An attacker can submit the JavaScript code snippet mentioned above to the form, which might not properly sanitize the input before displaying it on the webpage. When other users visit the affected page, the injected JavaScript will execute in their browser without their consent, potentially allowing the attacker to access sensitive user data.

Mitigation Steps

The Silverstripe CMS development team has addressed this vulnerability in version 4.11.1.

To protect your website and its users, perform the following steps

1. Update your Silverstripe CMS to the latest version (4.11.1 or newer) by following the update instructions from the Silverstripe CMS documentation: https://docs.silverstripe.org/en/4/upgrading/
2. Ensure all custom modules or code follow secure coding best practices and use proper output encoding to prevent XSS attacks.
3. Conduct regular security audits and vulnerability assessments of your website to detect and fix any weaknesses in your code.

Conclusion

The XSS vulnerability (CVE-2022-37421) found in Silverstripe CMS versions up to and including 4.11. presents a serious threat to website security and user privacy. Equipped with the details, exploit steps, and mitigation information provided in this post, you should be able to address this vulnerability and safeguard your website from potential attacks. It's essential to keep your CMS software updated and follow best practices for secure coding to minimize the risk of vulnerabilities and exploits.

Timeline

Published on: 11/23/2022 03:15:00 UTC
Last modified on: 11/30/2022 14:43:00 UTC