CVE-2024-9966 is a security vulnerability found in Google Chrome versions prior to 130..6723.58. The bug affects the way the browser implements navigations, allowing a remote attacker to potentially bypass the built-in Content Security Policy (CSP) by using a crafted HTML page. While Chromium, the open-source project behind Google Chrome, considers the severity of this vulnerability to be low, it is still vital to understand how it works and ensure you are protected.

Background

Content Security Policy is a crucial security measure employed by modern web browsers like Google Chrome to prevent cross-site scripting (XSS), clickjacking, and other code injection attacks. It achieves this by defining approved sources of content and blocking any content that doesn't originate from these sources.

In some cases, however, attackers may exploit vulnerabilities within the browser itself to bypass these security measures, potentially leading to malicious content being executed on the user's system. CVE-2024-9966 is one such vulnerability.

Exploit Details

This vulnerability specifically targets the navigation aspect of Google Chrome's implementation, exploiting a shortcoming that allows an attacker to override the content security policy settings by embedding a specially crafted HTML page.

To understand how this works, let's dive into some example code snippets. To abuse this vulnerability, an attacker might create an HTML page like this:

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="Content-Security-Policy" content="default-src 'none';">
</head>
<body>
  <iframe src="data:text/html;base64,PHNjcmlwdD5hbGVydCgnQ3Jvc3Mgc2lZSdzY3JpcHRpbmcgdmlhIENWRSyMDILTk5NjYnKTs8L3NjcmlwdD4=">
  </iframe>
</body>
</html>

This code snippet demonstrates how the attacker sets up a strict CSP that blocks most content, including scripts, to give users a false sense of security. However, the attacker also embeds an iframe that contains a Base64-encoded script capable of executing malicious code.

Due to the vulnerability in Google Chrome (versions prior to 130..6723.58), the browser fails to enforce the strict CSP defined, allowing the script in the iframe to execute. Consequently, the attacker's controlled script runs, and the message "Cross site scripting via CVE-2024-9966" is displayed, indicating a successful exploit.

You can learn more about this vulnerability and its details from the following sources

1. Chromium Bug Tracker: Issue 1283346
2. NVD - CVE-2024-9966 Detail
3. Google Chrome Releases Blog

Mitigation

To protect yourself from falling prey to this vulnerability, it is essential to keep your Google Chrome browser up to date. If you haven't already, update your Chrome to the latest stable version (130..6723.58 or later) to patch this vulnerability and ensure your browsing experience remains safe and secure.

Conclusion

While CVE-2024-9966 is classified as a "low" severity vulnerability, it is still a reminder that even well-established security measures like Content Security Policy can be bypassed. By keeping your browser up to date and understanding how these exploits work, you can take steps to mitigate your risk and continue enjoying a safe browsing experience.

Timeline

Published on: 10/15/2024 21:15:12 UTC
Last modified on: 10/17/2024 20:12:09 UTC