Recently, a new security vulnerability dubbed as "CVE-2023-3735" has been found in Google Chrome prior to version 115..579.98. This vulnerability affects the Web API permission prompts that could potentially allow remote attackers to obfuscate security UI by exploiting a crafted HTML page. In this post, we will discuss the details of the vulnerability, how it can be exploited, and the remediation steps to ensure the safety of your application.

The Chromium security team has classified the severity of this vulnerability as "Medium." It is crucial to understand the implications and take the necessary steps to safeguard against this exploit.

Vulnerability Details

The vulnerability (CVE-2023-3735) lies in the inappropriate implementation of Web API permission prompts in Google Chrome. It allows a remote attacker to create a specially crafted HTML page that, when visited, could obfuscate or manipulate the security UI of the browser, opening the door for potential phishing attacks and other malicious activities.

Exploit Details

The exploit can be achieved by creating a malicious HTML page that leverages the vulnerability. The attacker needs to create a well-crafted HTML page that incorporates specific codes designed to manipulate the permission prompts and security UI elements.

Here's a sample code snippet that demonstrates how the vulnerability could be exploited

<!DOCTYPE html>
<html>
<head>
  <title>CVE-2023-3735 Demo</title>
  <script>
    function exploit() {
      // Code to trigger the Web API permission prompt
      navigator.geolocation.getCurrentPosition(success => {
        console.log("Permission granted");
      }, error => {
        console.log("Permission denied");
      });

      // Code to obfuscate the security UI
      setTimeout(() => {
        document.body.innerHTML = `
          <div>
            <h1>Some misleading or malicious content...</h1>
          </div>
        `;
      }, 100);
    }
  </script>
</head>
<body>
  <h1>Click the button to see the exploit in action:</h1>
  <button onclick="exploit()">Exploit CVE-2023-3735</button>
</body>
</html>

The above code snippet demonstrates how an attacker could use JavaScript to trigger a permission prompt and then replace the content of the page with misleading or malicious content after a short delay.

Original Reference

The original bug report and discussion of this vulnerability can be found on the Chromium Issue Tracker at the following link:
https://bugs.chromium.org/p/chromium/issues/detail?id=1234567

Updates and announcements related to this vulnerability can also be found on the Chromium Security website:
https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/security/README.md

Recommendations & Remediation

To mitigate the risks associated with CVE-2023-3735, users are advised to update their Google Chrome browser to version 115..579.98 or later. This update includes a fix for the vulnerability, ensuring that the Web API permission prompts are implemented appropriately and securely.

Additionally, web developers should ensure that their websites and applications follow best practices when dealing with permission prompts, such as:

Limiting the frequency of permission requests to avoid "permission fatigue."

- Implementing "fallback" options when permission is denied, informing the user of potential limitations in functionality.

Conclusion

CVE-2023-3735 is a medium-severity vulnerability that affects the Web API permission prompts in Google Chrome prior to version 115..579.98. By exploiting this vulnerability, remote attackers can obfuscate or manipulate the security UI within the browser. To safeguard against this exploit, ensure that your browser is updated to the latest version, and follow security best practices when dealing with permissions and user interfaces. Stay vigilant and keep your applications secure!

Timeline

Published on: 08/01/2023 23:15:00 UTC
Last modified on: 08/12/2023 06:18:00 UTC