In this long-read article, we will dive deeper into the CVE-2023-21794 vulnerability that has been discovered recently, it targets Microsoft Edge (Chromium-based) browser which allows potential attackers to perform a spoofing attack. We will be discussing the exploit details, code snippets, and providing links to original references, all while using simple American English language to make it easy for everyone to grasp the content.

Before we start discussing the vulnerability itself, let's have a quick look at what Microsoft Edge (Chromium-based) browser is and how it's growing in popularity.

Microsoft Edge (Chromium-based)

Microsoft Edge is the latest web browser developed by Microsoft, it is based on the Chromium project which is an open-source web browser platform, developed and maintained by Google. This chromium foundation has made Edge faster, more secure, and compatible with a significant proportion of websites, thus increasing its popularity among users in recent years.

Now let's dive into the details of CVE-2023-21794 vulnerability.

CVE-2023-21794 Vulnerability

According to its CVE entry [1], this vulnerability can be categorized as a spoofing vulnerability that affects Microsoft's Edge (Chromium-based) browser. An attacker who can successfully exploit this vulnerability can potentially trick users into believing they are visiting a legitimate website when it could be a malicious one.

This attack is mainly performed by manipulating certain visual elements of the browser which are supposed to provide reliable information on the website's identity. In simpler terms, attackers take control of some browser features to make it appear as if you are visiting a secure and trusted website while, under the hood, you are interacting with a malicious one.

Exploit Details

The exploit can be executed by manipulating the URL displayed in the browser's address bar, specifically by using a combination of special characters and encoding. For example, the attacker can craft a malicious URL that looks extremely similar to the legitimate URL, this way deceiving the user into believing they are visiting the authentic site.

Here's an example code snippet of how this type of URL spoofing attack might look like

<!DOCTYPE html>
  <title>Malicious Website</title>
    function spoofUrl() {
      let maliciousUrl = '';;
      let encodedUrl = encodeURIComponent(maliciousUrl);
      let legitUrl = ''; + encodedUrl;
      window.history.pushState('', '', legitUrl);
<body onload="spoofUrl()">
  <h1>Welcome to our legit-looking malicious website!</h1>

In the code snippet above, the attacker has crafted a URL that resembles the legitimate URL, and as soon as the user visits the malicious site, the spoofUrl() function is executed, manipulating the browser's address bar to make it look as if they are on the legitimate site.

References and Vulnerability Fix

To prevent such attacks, Microsoft has already provided a fix for this vulnerability that can be found in their security advisory [2]. The fix contains several measures to ensure that visual indicators are correctly displayed, and attackers can no longer exploit this vulnerability. It is highly advisable for users to keep their Microsoft Edge browser updated to the latest version in order to stay protected from such threats.

In conclusion, the CVE-2023-21794 vulnerability serves as a reminder of how important it is to keep your software up-to-date and be aware of the potential risks that exist in our digital world today. By understanding the details of these vulnerabilities and how they can be exploited, we can better protect ourselves and our systems from potential harm.



Published on: 02/14/2023 20:15:00 UTC
Last modified on: 02/23/2023 16:07:00 UTC