

Every website and download is checked against a local list of popular legitimate websites if the site is not listed, the entire address is sent to Microsoft for further checks. With the release of Internet Explorer 8, the Phishing Filter was renamed to SmartScreen and extended to include protection from socially engineered malware. Phishing Filter does not check every website visited by the user, only those that are known to be suspicious.

SmartScreen was first introduced in Internet Explorer 7, then known as the Phishing Filter. SmartScreen in Internet Explorer Internet Explorer 7: Phishing Filter

SmartScreen as a business unit includes the intelligence platform, backend, serving frontend, UX, policy, expert graders, and closed-loop intelligence (including machine learning and statistical techniques) designed to help protect Microsoft customers against safety threats like social engineering and drive-by downloads. SmartScreen intelligence is also used in the backend of Microsoft's online services such as the web app and Microsoft Bing search engine. SmartScreen (officially called Windows SmartScreen, Windows Defender SmartScreen and SmartScreen Filter in different places) is a cloud-based anti-phishing and anti-malware component included in several Microsoft products, including operating systems Windows 8 and later, the applications Internet Explorer, Microsoft Edge.
