In June 2018 the existence of secret Office 365 forensics tool was confirmed. The tool refers to Microsoft’s undocumented Exchange Online Activities API. The API provides access to a granular mail activity events for up to six months old data!

To provide administrators with easy access to the API, I created a PowerShell module (EXOMailActivity). In this blog, I’ll show you how to use the module to get access to mail activity data.