So here are the ways in which you can prevent the Data Loss via Email. The policies below are available with Exchange Plan 1.
Email DLP using Exchange Plan 1:
Restrict certain users to send emails only to Company users.
Auto Forward messages to a sender’s manager for approval
Block messages with executable attachments
Setup Spam Confidence levels for Incoming Emails
Organization wide message disclaimers, signatures, footers
Forward message that contains sensitive information
Forward messages that match one of the several criteria
Setting up policy tips if there is policy violation
Supervisor Mailbox. All messages can be copied to this account or just those sent internally or externally. This feature is very useful in preventing data leakage via email.
Prevent download of attachment in Browser. View only
Block browser access for email. Access only on Outlook app.
Archive mailbox – Users can use the archive mailbox, also called a personal archive, to store historical messaging data by moving or copying messages from their primary mailbox to their archive mailbox.
Retention Policies – Retention policies use retention tags to apply retention settings to e-mail messages and folders. Retention tags define an age limit that specifies how long items are retained, and a retention action that specifies what happens to items that reach the retention age limit.
Sensitivity Labels. We can manually create the labels and apply to Documents which will help us to prevent Data Loss.