Microsoft security researchers discovered an unusual phishing campaign which uses custom 404 error pages to trick potential victims into handing out their Microsoft credentials. The phishing pages are camouflaged as legitimate Microsoft account sign-in pages, down to the smallest details. The victims are then redirected to a real Microsoft login form masked with a shortened URL after successfully harvesting the credentials. Microsoft has added the URLs used in this campaign to its SmartScreen’s list of reported phishing, malware, exploit, and scam sites. Google is yet to add it to its Safe Browsing blacklist service.
Source: https://www.bleepingcomputer.com/news/security/microsoft-warns-of-phishing-attacks-using-custom-404-pages/