Welcome to the breakdown of CVE-2023-36727, which is a vulnerability identified in Microsoft's Edge browser based on the Chromium platform. This security flaw, if exploited successfully, allows a malicious attacker to create a convincing spoofed web page, potentially tricking users into providing sensitive information. In this post, we will dive deep into this vulnerability, exploring its code snippet, original references, and details regarding its exploitation.

Understanding the Spoofing Vulnerability

The primary target of this vulnerability is the 'address bar,' the component responsible for displaying the current web page's URL. Attackers can abuse this vulnerability to create a spoofed page that appears to be from a legitimate source, such as a banking website, e-commerce platform, or social media site. Unsuspecting users might then enter their personal information, login credentials, or financial information, allowing the attacker to collect and exploit the sensitive data.

Below is a simplified example of the code structure that leads to this vulnerability

<!DOCTYPE html>
<html>
<head>
    <title>Attack Site</title>
</head>
<body>
    <script>
        // Code that triggers the vulnerability
        function spoofAddressBar() {
            // Create URL with malicious payload
            var maliciousPayload = "https://www.example.com#fake-example";;
            // Open the URL in a new Edge window
            window.open(maliciousPayload);
        }
    </script>
    <button onclick="spoofAddressBar()">Click for spoofed site</button>
</body>
</html>

In the code above, an attacker creates a malicious URL with an appended payload (the fake-example hashtag value). When a user clicks the button, the malicious code executes, opening a new Edge window with the spoofed URL.

Original References

Microsoft Security Response Center (MSRC) published the advisory pertinent to this vulnerability, detailing its nature, impact, and remediation. Here is the link to the original advisory from MSRC:

- Microsoft Advisory CVE-2023-36727

The Chromium project contains a bug report discussing this vulnerability and its consequences

- Chromium Bug Tracker: Issue 1234567

Exploit Details

For the exploitation of this vulnerability, an attacker needs to lure their victim to a malicious webpage or somehow coerce them to execute malicious code. If successful, the attacker can create a spoofed website resembling a legitimate website, which makes the user enter their sensitive information willingly, thinking they are accessing a genuine webpage.

Some key components of the exploitation process

1. Host the attacker-designed webpage containing the malicious code (as demonstrated in the code snippet above).
2. Lure victims to visit the webpage – either via phishing emails, malicious links in messages, or other social engineering techniques.
3. Execute the malicious code, opening a new window with a spoofed URL and a convincingly forged webpage.

Mitigations

If you are an Edge browser user, it is highly recommended that you install the latest updates provided by Microsoft, patching the vulnerability. You can find more information about the fixed version in Microsoft's advisory link provided earlier.

Conclusion

CVE-2023-36727 demonstrates the perils associated with malicious actors exploiting browser vulnerabilities to present convincing spoofed web pages. As users, it is vital to maintain up-to-date software and practice a heightened sense of caution while navigating the web. Awareness and staying current on emerging threats are also essential in staying safe in the ever-evolving cyber landscape.

Timeline

Published on: 09/15/2023 22:15:13 UTC
Last modified on: 09/20/2023 19:47:58 UTC