Browser-in-the Browser

A novel phishing technique called browser-in-the-browser (BitB) attack can be exploited to simulate a browser window within the browser in order to spoof a legitimate domain, thereby making it possible to stage convincing phishing attacks.

According to penetration tester and security researcher, who goes by the handle mrd0x_, the method takes advantage of third-party single sign-on (SSO) options embedded on websites such as “Sign in with Google” (or Facebook, Apple, or Microsoft).

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While the default behavior when a user attempts to sign in via these methods is to be greeted by a pop-up window to complete the authentication process, the BitB attack aims to replicate this entire process using a mix of HTML and CSS code to create an entirely fabricated browser window.

Browser-in-the Browser

“Combine the window design with an iframe pointing to the malicious server hosting the phishing page, and it’s basically indistinguishable,” mrd0x_ said in a technical write-up published last week. “JavaScript can be easily used to make the window appear on a link or button click, on the page loading etc.”

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While this method significantly makes it easier to mount effective social engineering campaigns, it’s worth noting that potential victims need to be redirected to a phishing domain that can display such a fake authentication window for credential harvesting.

“But once landed on the attacker-owned website, the user will be at ease as they type their credentials away on what appears to be the legitimate website (because the trustworthy URL says so),” mrd0x_ added.

Posted by Charlie