In the evolving landscape of cybersecurity threats, phishing attacks remain a prevalent and dangerous method for compromising sensitive information. This thesis investigates the Browser-in-the-Browser (BitB) attack, a sophisticated phishing technique designed to deceive users by mimicking legitimate browser windows within their actual browser. Unlike traditional phishing methods, which rely on fake websites or email scams, BitB attacks create highly convincing, simulated browser windows that appear authentic to the user. The BitB attack works by embedding a fake browser window within a legitimate one, often as a pop-up or new tab. This fake window is crafted to look identical to a real browser window, complete with realistic URL bars, SSL certificate indicators, and other interface elements.