How can an Exchange administrator use PowerShell to add persistent email access to a user's mailbox?

An administrator can run PowerShell commands on the Exchange server using the `Microsoft.Exchange.Management.PowerShell.SnapIn` snap-in. To grant user test2 full access (Owner) to test1's inbox, they execute `Add-MailboxFolderPermission -Identity [email protected]:\Inbox -User [email protected] -AccessRights Owner`. This gives test2 persistent access. To view current permissions, use `Get-MailboxFolderPermission`, and to remove, use `Remove-MailboxFolderPermission`. For more on Exchange management, see Penetration Techniques - From Exchange File Read/Write Permissions to Command Execution.