Although DACL permissions are not the easiest topic to cover in one post and should be digested slowly, there are examples of potential attack scenarios we want to share. The following blog tries to shed some light on the subject, present the possible escalation paths and suggest relevant mitigations.
Administrators have always been able to access user content and don’t need eDiscovery functionality to do this. Administrators can log onto someone’s mailbox or give themselves permission to access a user’s OneDrive account, or use the Search-Mailbox cmdlet to copy messages from user mailboxes to another mailbox. And they can run content searches to scan mailboxes, SharePoint, OneDrive, Teams, Office 365 Groups, and public folders and export whatever they find to PST files, ZIP files, or individual files. In short, many ways are available to an Office 365 administrator to poke around in user content if they so wish. Continue reading → Verifying Administrator Access to Office 365 User Data