In July Microsoft released their OWA app for iPhone and iPad. The feedback regarding this app has been excellent however it has raised questions about information security. The default setting for each user mailbox allows the app to connect, therefore it is important to be able to disable the app if required. This can be done using both the portal and PowerShell.
Logon to the Exchange Admin Center in the portal and select Recipients | Mailboxes. Highlight the relevant user and select ‘Disable OWA for Devices‘
As you can guess this could get a bit laborious with a few thousand users so PowerShell comes to the rescue. This feature is managed by the Set-CASMailbox cmdlet.
Set-CASMailbox firstname.lastname@example.org -OWAforDevicesEnabled $false
The command above will disable the app for the relevant person listed, and scripts can be developed to apply this to multiple people.