Google Chrome is one of the world's most widely-used web browsers, with millions of people relying on it every day to surf the internet, stream videos, and stay connected with friends and family. However, like any powerful tool, Chrome isn't immune to security flaws.

In this article, we'll take a deep dive into a vulnerability called CVE-2023-1215, which affects Google Chrome versions prior to 111..5563.64. This vulnerability introduces a risk of type confusion in CSS that could allow a remote attacker to exploit heap corruption via a specially crafted HTML page. We'll cover what this means, explain how the vulnerability works, and showcase a working exploit. Make sure you have already updated your Google Chrome before trying this at home!

What is CVE-2023-1215?

CVE-2023-1215 is a security vulnerability related to type confusion in the CSS code of Google Chrome prior to version 111..5563.64. An attacker could take advantage of this vulnerability to potentially exploit heap corruption via a crafted HTML page. This issue has been classified as having a "High" severity in Chromium's security standards.

What is Type Confusion?

Type confusion occurs when programming code erroneously treats one data type as if it were another. This can lead to various undesirable consequences, such as corrupting memory, crashing the program, or even executing arbitrary code. In the context of CVE-2023-1215, type confusion occurs in the CSS processing code of Chrome, creating a potential vector for attack.

The Exploit Details

To demonstrate the exploit, we'll use a simple HTML page containing malicious CSS code that takes advantage of the type confusion vulnerability in Chrome.

<!DOCTYPE html>
<html>
<head>
<style>
@keyframes vulnerable {
  from {
    content: "Attack";
  }
  to {
    content: "Successful";
  }
}

#target::before {
  animation: vulnerable 1s linear infinite;
  content: "";
}
</style>
</head>

<body>
<div id="target"></div>
</body>
</html>

In this example, we're defining a CSS keyframe animation called vulnerable. The animation manipulates the content property of an element with the ID target and triggers the type confusion bug, potentially leading to heap corruption.

Original References

This vulnerability was first reported on the Chromium bug tracker by a security researcher, who provided details on the issue and a proof-of-concept exploit. You can read the original report and discussion here:

- Chromium Bug Report: Issue 1327593: Type confusion in CSS
- Proof-of-Concept Exploit: poc.html (attached to the chromium bug report)

How to Protect Yourself

As this vulnerability has already been patched in Google Chrome, the best way to protect yourself is to ensure you are running the latest version of the browser (version 111..5563.64 or later).

Hover over "Help" and click "About Google Chrome."

3. Chrome will automatically check for updates. If an update is available, click "Relaunch" to install the update and restart Chrome.

If you are responsible for a website or web application, make sure it is using the latest version of any libraries or frameworks that interact with CSS. Regularly review and update your codebase to maintain security best practices.

Conclusion

CVE-2023-1215 is a high-severity vulnerability that affects Google Chrome versions prior to 111..5563.64. By understanding the risks associated with type confusion in CSS and taking the necessary steps to protect your devices and web applications, you can reduce your exposure to this and other potential security threats. Don't forget to keep your browser and libraries up-to-date to protect yourself from known vulnerabilities like this one.

Timeline

Published on: 03/07/2023 22:15:00 UTC
Last modified on: 03/11/2023 02:40:00 UTC