Microsoft Exchange and Office365 are extremely popular products that organizations use for enterprise email. These services can be exploited by remote attackers to potentially gain access to Active Directory user credentials. In this Tradecraft Security Weekly episode Beau Bullock (@dafthack) demonstrates how to utilize MailSniper to enumerate internal domains, enumerate usernames, perform password spraying attacks, and get the global address list from Exchange and Office365 portals.

Links: MailSniper - https://github.com/dafthack/MailSniper