This article explores a phishing technique that simulates a browser window within the browser to spoof a legitimate domain.

For security professionals, the URL is usually the most trusted aspect of a domain. Yes there’s attacks like IDN Homograph and DNS Hijacking that may degrade the reliability of URLs but not to an extent that makes URLs unreliable.

All of this eventually lead me to think, is it possible to make the “Check the URL” advice less reliable? After a week of brainstorming I decided that the answer is yes.
Pop-Up Login Windows

Quite often when we authenticate to a website via Google, Microsoft, Apple etc. we’re provided a pop-up window that asks us to authenticate. The image below shows the window that appears when someone attempts to login to Canva using their Google account.

Fortunately for us, replicating the entire window design using basic HTML/CSS is quite simple. Combine the window design with an iframe pointing to the malicious server hosting the phishing page, and its basically indistinguishable. The image below shows the fake window compared with the real window. Very few people would notice the slight differences between the two.

JavaScript can be easily used to make the window appear on a link or button click, on the page loading etc. And of course you can make the window appear in a visually appealing manner through animations available in libraries such as JQuery.

Hovering over a URL to determine if it’s legitimate is not very effective when JavaScript is permitted. HTML for a link generally looks like this:

[align=center]<a href="https://gmail.com">Google</a>[/align]