2. Block attachments used for malware
Again, Office 365 and Microsoft Exchange offer some robust anti-malware capabilities out of the box, including multiple anti-malware scan engines, real-time threat response, and rapid integration of new patches and malware definitions to respond quickly to new threats. But you can go even further by blocking email attachments of files that are commonly used for malware.
Just sign into the Office 365 Security and Compliance center, look under Threat Management and select Policy, then Anti-Malware. Double-click the default policy, then click Settings. Turn on Common Attachment Types—in the future, you can add or remove attachment types as needed. This step will add another layer of protection for your network in the event that authorized employees are careless about opening suspicious messages.
3. Create anti-ransomware mail flow rules
For improved Office 365 email security, prevent hackers from locking you out of your own data systems and even your devices. You’ll need to create mail flow rules that block attachments commonly used for ransomware. Just open the admin center for Exchange, click on Rules under Mail Flow, then click Create a New Rule. You’ll be presented with a wide range of options that allow you to either block emails that could contain ransomware and other malicious code, or to preemptively warn users who receive such emails.
A ransomware attack can be one of the most financially damaging forms of online threat. It’s better to be particularly cautious in this arena and favor stringent rules, rather than leave the door open to emails with malicious code.