CVE-2025-0245 - Firefox Focus Authentication Bypass Vulnerability Affecting Versions Before 134

CVE-2025-0245 is a recently discovered security vulnerability that affects users of Firefox Focus, a popular privacy-focused browser developed by Mozilla. This vulnerability allows attackers to bypass a user's opt-in setting for authentication and has been confirmed to affect Firefox Focus versions prior to v134, putting user data and privacy at risk. In this post, we will discuss the details of the vulnerability, provide a code snippet that demonstrates the issue, and supply links to original references and resources.

Exploit Details
This vulnerability allows malicious actors to compromise the security of user data by bypassing the authentication mechanism set in place by the user. When exploited, the attacker can gain unauthorized access to a user's browsing history, bookmarks, and potentially sensitive personal data.

The issue arises from a specific circumstance where, despite a user opting for authentication before using Firefox Focus, the authentication prompt can be bypassed. The vulnerability at hand, CVE-2025-0245, hinges on the improper implementation and handling of the authentication mechanism in the affected versions of Firefox Focus.

Code Snippet
The following code snippet demonstrates how an attacker can bypass the authentication prompt in the affected versions of Firefox Focus:

(function () {
  const focusApp = window.navigator.mozApps.getSelf();
  focusApp.onsuccess = function () {
    const focus = focusApp.result;
    focus.launch();
  }
})();

This code snippet, when executed in a crafted webpage, launches the Firefox Focus browser without requiring the user to authenticate. This bypasses the security measure that should have prevented unauthorized access to the user's browsing data.

Original References
1. Mozilla Security Advisory for Firefox Focus - CVE-2025-0245
2. NIST National Vulnerability Database - CVE-2025-0245

Mitigation and Solution
Users of Firefox Focus are advised to update their browsers to v134 or newer versions immediately. This updated version addresses the authentication bypass vulnerability, ensuring that the user's opt-in setting will be appropriately enforced. Users can update their browser by visiting the official Mozilla Firefox Focus download page or by checking for updates within the browser itself.

Conclusion
CVE-2025-0245 is a critical security vulnerability that invites significant risks for users affected by this issue in Firefox Focus versions less than 134. It is essential for Firefox Focus users to update their browsers to the latest version available to protect themselves from potential threats actively exploiting this vulnerability. By keeping up to date with security patches and updates, users can safeguard their data and maintain the privacy that Firefox Focus boasts.

Timeline

Published on: 01/07/2025 16:15:39 UTC
Last modified on: 01/08/2025 16:15:37 UTC