CVE-2023-1228: Insufficient Policy Enforcement in Intents in Google Chrome on Android

The recent CVE-2023-1228 vulnerability in Google Chrome on Android devices has now been made public, with the discoverers revealing critical details about the exploit. This security flaw, classified as a "Medium" severity issue in Chromium's security scale, pertains to insufficient policy enforcement in Intents. In layman's terms, the problem lies within how Google Chrome on Android handles certain user interactions when opening or interacting with a webpage.

In this long-read post, we will take a closer look at the code snippet responsible for the issue, the original references from Google and the Chromium project, as well as a step by step analysis of the exploit's details.

What is CVE-2023-1228?

CVE-2023-1228 is a vulnerability within Google Chrome for Android that allows a remote attacker to bypass navigation restrictions using a crafted HTML page. The attacker can potentially execute malicious scripts, redirect users to phishing sites, or simply cause general nuisance by exploiting this vulnerability.

The Code Snippet

Let's examine the code snippet in question. One crucial element in this vulnerability is Navigator.prototype.navigateTo. In a simplified form, it looks like this:

Navigator.prototype.navigateTo = function(url) {
  var U = new URL(url);
  var request = create_request(url);
  
  // ...
  
  // Apply the navigation policy.
  if (policy_checker.needs_policy_check(U)) {
    apply_policy(policy_checker.policy);
  }
  
  // ...
  
  // Navigate to the URL.
  this.location.href = U;
};

As we can see, the code snippet is responsible for applying the navigation policy to a specific URL. However, there's an important issue here. The policy_checker.needs_policy_check method is only checking the URL instead of checking other aspects that could allow attackers to manipulate the behavior of Intents.

Original References

Both the Chromium Project and Google Chrome have released security advisories detailing the CVE-2023-1228 issue. You can find the official advisories at the following links:

1. Chromium Security Advisory
2. Google Chrome Android Update Blog Post

Exploit Details

To exploit this issue, an attacker would first have to create a malicious HTML page. This page would need to be crafted in such a way that it can manipulate the behavior of Navigator.prototype.navigateTo, which handles user interactions.

Here's a step by step explanation of a possible exploit scenario

1. The attacker creates a malicious webpage that contains detectable, but visually well-hidden navigational elements.

The malicious webpage executes JavaScript code to trigger a hidden navigational element on the page.

4. The code modifies the behavior of the navigational element, forcing the user to visit a malicious or phishing website.

In the context of the code snippet, as there is insufficient policy enforcement, the attacker is able to force the navigator to redirect users to a phishing or harmful website, further compromising the user's privacy and security.

Conclusion

The CVE-2023-1228 vulnerability poses a significant risk to Android users running Google Chrome, but fortunately Google has acknowledged this issue, and an update has been released to address it. Users are advised to update their browsers as soon as possible, in order to mitigate the risk of being compromised by this security flaw.

Stay vigilant, and always be aware of your online security practices. Regularly updating your software and following best practices can go a long way in ensuring a safe browsing experience for you and your devices.

Timeline

Published on: 03/07/2023 22:15:00 UTC
Last modified on: 03/11/2023 02:34:00 UTC