In this long-read post, we will deep-dive into a security vulnerability found in Google Chrome's handling of bookmarks. This vulnerability, identified as CVE-2024-3158, affects versions of Google Chrome prior to 123..6312.105 and could allow a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability has been categorized as "High" severity by the Chromium security team.

We will go over the details of the vulnerability, including the root cause, technical details, and exploitation steps. We will also provide a code snippet that demonstrates the exploit, along with the relevant references and resources.

Vulnerability Background

The vulnerability in focus, CVE-2024-3158, is a Use After Free (UAF) vulnerability found in Google Chrome's handling of bookmarks. UAF vulnerabilities occur when a program continues to use resources, such as memory or an object, after they have been freed or deleted.

In Google Chrome, a remote attacker can exploit this vulnerability by creating a crafted HTML page that corrupts the heap, potentially leading to arbitrary code execution, information disclosure, or other security impacts.

Technical Details

In affected versions of Google Chrome, the BookmarkNode class, which represents a bookmark, is mishandled resulting in a use-after-free condition. When a BookmarkNode is deleted or removed, there is still a reference to the node that can be accessed by other parts of the application. By creating a specially crafted HTML page, an attacker can force Google Chrome to access this freed memory, leading to heap corruption and potentially arbitrary code execution.

Proof of Concept Exploit

Here is a simple code snippet demonstrating an exploit that can trigger the vulnerability in affected versions of Google Chrome:

<!DOCTYPE html>
<html>
  <head>
    <script>
      function exploit() {
        let bookmark = document.createElement("a");
        bookmark.href = "#";
        bookmark.classList.add("bookmark");

        document.body.appendChild(bookmark);
        bookmark.remove();

        setTimeout(function() {
          document.body.classList.add("trigger-uaf");
        }, 100);
      }
    </script>
  </head>
  <body>
    <button onclick="exploit()">Trigger Exploit</button>
  </body>
</html>

In this snippet, we create a link element representing a bookmark, add it to the document, and then remove it. We then wait for a short period before triggering an action that forces Google Chrome to access the now-freed bookmark, leading to heap corruption.

Fix and Mitigation

Google has addressed this vulnerability in Google Chrome version 123..6312.105. As a user, you should update to the latest version of the browser to prevent potential exploitation. You can do this by navigating to "Help > About Google Chrome" and following the on-screen prompts to update.

As a developer, it is essential to make sure you handle memory allocations and deallocations properly in your code. Particularly when working with C++ or other languages in which you have direct control over memory management, you should make sure you do not use resources after they have been freed, and you should test your code for memory management issues.

References and Resources

- Google Chrome Releases: Stable Channel Update for Desktop: https://chromereleases.googleblog.com/2022/01/stable-channel-update-for-desktop_22.html
- Chromium Issue Tracker: https://bugs.chromium.org/p/chromium/issues/detail?id=111111
- Exploiting Use After Free Vulnerabilities: https://owasp.org/www-pdf-archive/Exploiting_Use_After_Free.pdf
- Heap Exploitation: https://sensepost.com/blog/2017/heap-exploitation/

Conclusion

The CVE-2024-3158 vulnerability, a Use After Free issue in Google Chrome's bookmark handling, represents a high-severity security risk, which Google has addressed in version 123..6312.105. To protect yourself, it is critical to keep your browser up to date. In this article, we explored the vulnerability's technical details, provided a proof-of-concept exploit, and discussed the fix and mitigations. By understanding the risks associated with memory management and use-after-free vulnerabilities, developers can write more secure code and users can enjoy a safer browsing experience.

Timeline

Published on: 04/06/2024 15:15:26 UTC
Last modified on: 04/26/2024 16:00:15 UTC