To reduce your risk from malware that may not be detected by Exchange Online Protection, you should enable file type blocking and file name extension blocking. This article describes how to do this.
- Sign in to the Exchange admin center.
- Click mail flow, click rules, click New (), and then click Create a new rule.
- In the Name box, specify a name for the rule, and then click More options.
- Under Apply this rule if, point to Any attachment, and then select has executable content near the bottom of the page.
- Under Do the following, point to Block the message, and then select the action that you want.
- Click save.
For more information about malware defense practices and strategies, see the following Microsoft TechNet resources:
Article ID: 2959596 - Last Review: 29 Dec 2016 - Revision: 1