CVE-2023-4900 is a vulnerability that affects Google Chrome on Android devices. This security flaw arises due to an improper implementation of custom tabs, allowing a remote attacker to obfuscate a permission prompt using a specially crafted HTML page. This article will dive into the details of this vulnerability, code snippets to illustrate the issue, original references, and steps to protect your applications against such attacks.

Introduction

Custom Tabs are a popular feature in Google Chrome that allows developers to provide an in-app browsing experience. However, an inappropriate implementation of custom tabs in versions prior to 117..5938.62 has left these browsers vulnerable to attacks. The Chromium project has assigned a medium security severity to this vulnerability, identified as CVE-2023-4900.

Let's take a closer look at how this vulnerability works and the potential risks it presents.

Vulnerability Details

The flaw lies in the way custom tabs handle permission prompts. A remote attacker can create a malicious HTML page that, when loaded in a custom tab on Chrome for Android, can obfuscate a vital permission prompt. This can trick users into granting intrusive permissions, leaving their devices vulnerable to further exploits and data theft.

Here's a code snippet to show how an attacker might create a malicious HTML page that takes advantage of the CVE-2023-4900 vulnerability:

<!DOCTYPE html>
<html>
<head>
  <title>CVE-2023-4900 Exploit</title>
  <script>
    function exploit() {
      // Crafted code to obfuscate permission prompt
      ...
    }
  </script>
</head>
<body>
  <button onclick="exploit()">Click to Exploit</button>
</body>
</html>

Original References

The Chromium team discovered and reported this vulnerability. You can find the original reference, along with its details and discussion, on the Chromium project's bug tracker:

- Issue 1318681: Inappropriate implementation in Custom Tabs

Exploitation and Impact

By exploiting this vulnerability, an attacker can deceive users into granting permissions they did not intend to grant. This could lead to attackers having unwarranted access to sensitive user information or control over device features, such as camera use or geolocation data. This makes it essential for users and developers to adopt the necessary measures to protect their applications and devices from potential attacks.

Mitigation and Protection

To safeguard against this vulnerability, it is crucial to update Google Chrome on Android to the latest version. The Chromium team has patched the issue in version 117..5938.62. Users can update their browsers through the Google Play Store, while developers should ensure their applications are utilizing the most recent version of Chrome custom tabs.

Furthermore, developers should employ best practices in handling permissions in their applications. This may include providing clear instructions and context for permission requests before presenting them to users, as well as offering easy ways to revoke or modify permissions as needed.

Conclusion

CVE-2023-4900 is a medium-severity vulnerability that affects custom tabs in Google Chrome for Android. Due to an inappropriate implementation, a remote attacker can obfuscate a permission prompt via a crafted HTML page, potentially leading to unauthorized access to sensitive information or device features. To protect against this vulnerability, users should update to the latest version of Google Chrome on Android, and developers should follow best practices for handling permissions in their applications.

Timeline

Published on: 09/12/2023 21:15:08 UTC
Last modified on: 10/17/2023 20:12:54 UTC