Security reports
Defender for Office 365 includes a suite of reports to showcase the efficacy of its security measures. These reports can provide visibility on changes or events in your environment that might not have been triggered by any alerts yet indicate the presence of a sophisticated bad actor in the environment. Mature security teams establish processes to periodically review these reports and validate the behavior reported on them. You can locate most of these reports by visiting the Defender portal (security.microsoft.com); on the left-hand menu, go to the Reports section and follow this path: Reports | Email & collaboration | Email & collaboration reports, or you can directly access it via the security.microsoft.com/emailandcollabreport URL. There are also some mail-specific reports included with the Exchange admin center (EAC) (admin.exchange.microsoft.com), which can be accessed from the left-hand menu by selecting Reports and either selecting Mail flow or Migration...