CVE-2024-43577 - Microsoft Edge (Chromium-based) Spoofing Vulnerability Explained

On May 2024, a major spoofing vulnerability was identified in the Microsoft Edge browser (Chromium-based). Cataloged as CVE-2024-43577, this flaw could let attackers trick users into sharing sensitive information through fake websites that appear legitimate. Let’s break down what CVE-2024-43577 is, how it works, and how you can protect yourself.

What is a Spoofing Vulnerability?

Spoofing means faking something to gain trust. In the context of browsers, a spoofing vulnerability can allow attackers to make a malicious website look like a real one. This could result in users unintentionally sharing sensitive info, thinking they’re interacting with a trusted site—such as their bank or email.

CVE-2024-43577: The Details

CVE-2024-43577 affects Chromium-based Microsoft Edge (the new version built on Google’s Chromium engine). According to Microsoft Security Response Center (MSRC), a flaw in the browser’s URL handling allows attackers to display fake URLs in the address bar.

The end result? Malicious sites can pretend to be real ones, increasing the risk of phishing and data theft.

Severity: Important
Attack Vector: Remote
Patch Status: Fixed in Edge Version 124..2478.67 and above

Technical Breakdown: How Does It Work?

The vulnerability is related to the way Edge manages site navigation and handles embedded content, such as iframes or specially crafted redirects. By exploiting a flaw in the handling of navigation events, a malicious website can trick Edge into rendering a different page than what is shown in the address bar.

2. The attacker uses script or HTML tricks (e.g., through an iframe or window.open with manipulated parameters) to change the visible address without changing the content.
3. Edge incorrectly shows the trusted site’s URL in the address bar, even though the page content is malicious.

Example Code: Spoofing the Address Bar

Here’s a simplified example—for educational purposes only—showing how an attacker might exploit the vulnerability:

<!-- attacker.html -->
<!DOCTYPE html>
<html>
<head>
    <title>Attacker’s Spoofing Demo</title>
    <script>
        // Wait until page loads
        window.onload = function() {
            // Open a window to trusted.site.com, but quickly inject malicious content
            let win = window.open('https://trusted.site.com';, '_blank');
            setTimeout(function() {
                // Exploit: inject malicious code/content
                if(win) {
                    win.document.body.innerHTML = '<h1>Fake Login Page</h1><form>...</form>';
                    win.location.hash = ''; // tries to prevent user noticing
                }
            }, 100);
        };
    </script>
</head>
<body>
    Loading...
</body>
</html>

Note: Modern browsers have anti-spoofing protections, but the exploit would use a more advanced variation that abuses CVE-2024-43577’s flaw in navigation handling.

Real-World Impact

When a user clicks a malicious link (say, in a phishing email or ad), the forged site appears to be from a trusted organization, complete with a fake URL. Below is what the user might see in Edge’s address bar:

https://yourbank.com

But the content is actually from the attacker’s server.

Be wary of clicking on links in emails or messages from unknown sources.

- Double-check website security by looking for HTTPS and clicking the lock icon to inspect certificates.

Conclusion

CVE-2024-43577 is a clear reminder that even trusted browsers can have serious flaws. Always keep Edge updated, be careful with links, and stay informed about the latest security news.

Have you updated Microsoft Edge recently? If not, now is the time—this one’s important. Stay safe out there!

Timeline

Published on: 10/18/2024 23:15:06 UTC