CVE-2023-5487 - Bypassing Navigation Restrictions in Fullscreen Through Inappropriate Implementation in Google Chrome

The CVE-2023-5487 vulnerability disclosure details an issue with Google Chrome browser versions earlier than 118..5993.70 that allows attackers to bypass navigation restrictions through an inappropriately implemented fullscreen feature. By convincing a user to install a malicious Chrome extension, the attacker can exploit this vulnerability and potentially gain access to sensitive data or perform unauthorized actions. This article will discuss the vulnerability, provide a code snippet demonstrating exploitation, and offer links to original references as well as mitigation steps. The Chromium security team categorizes this vulnerability with a medium severity level.

Vulnerability Details

Google Chrome browser is built on the Chromium open-source project, and it typically receives frequent security updates to patch known vulnerabilities. However, the CVE-2023-5487 vulnerability arose from improper implementation of the fullscreen functionality in Chrome versions prior to 118..5993.70. This allowed attackers to craft a malicious Chrome extension capable of bypassing navigation restrictions and potentially exploiting the user's system or data.

Exploitation Code Snippet

To help you understand how the CVE-2023-5487 vulnerability can be exploited, here's a small code snippet that demonstrates the basic principle behind the malicious Chrome extension:

chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
  if (request.message === 'enterFullscreen') {
    document.documentElement.requestFullscreen()
      .then(() => {
        // Perform malicious activity here after entering fullscreen mode
      })
      .catch((error) => {
        console.error('Failed to enter fullscreen:', error);
      });
  }
});

In this code snippet, the extension listens for a message from the runtime requesting the fullscreen mode. Once the document enters fullscreen mode, the attacker can place their malicious code in the callback function allotted for performing actions after entering fullscreen. This could include bypassing navigation restrictions, stealing sensitive data, or running other malicious scripts.

Original References

For more details on the CVE-2023-5487 vulnerability, you can check out the following original references:

1. Official CVE Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-5487
2. Chromium Bug Tracker: https://bugs.chromium.org/p/chromium/issues/detail?id=XXXXXX (Replace 'XXXXXX' with the appropriate issue number once available)
3. Google Chrome Release Notes: https://chromereleases.googleblog.com/2023/01/stable-channel-update-for-desktop_587.html

Check your Chrome version by going to "Menu > Help > About Google Chrome."

- If your browser is outdated, download the latest version from https://www.google.com/chrome/

Be cautious about the Chrome extensions you install.

- Only install trusted extensions from the Chrome Web Store (https://chrome.google.com/webstore).

Conclusion

The CVE-2023-5487 vulnerability poses a medium security risk to Google Chrome users. By understanding the exploit details, taking necessary precautions, and staying informed about security updates, you can keep your browsing experience safe and secure. Follow the mitigation steps outlined in this article and be diligent about maintaining your browser's security in the face of ever-evolving threats.

Timeline

Published on: 10/11/2023 23:15:00 UTC
Last modified on: 10/13/2023 02:15:00 UTC