Stop Auto-forwarding for E-mail

Stop auto-forwarding for E-mail 

Hackers who gain access to a user's mailbox can exfiltrate mail by configuring the mailbox to automatically forward email. This can happen even without the user's awareness. You can prevent this from happening by configuring a mail flow rule. 

• Go to your Office Portal and select Admin app (this will only be visible if you are an admin in your organization). 

• Once you reach your Admin Center, click on Show All. 

• Click on Admin Centers. 

• Click on Exchange. 

• In the screen that appears, go to Mail flow category, click on Rules. 

• In the rules, click on ‘+’. 

• A drop down appears. In the drop down, click on Create a new rule. 

• A pop-up window appears. In the pop-up window, type your rule name. 

• Scroll down to the bottom and then click on More options. 

• Apply the settings in the following table. Leave the rest of the settings at the default, unless you want to change these. 

• You can even add a message to your notifications if you want. 

• Click on Save. 

SOURCE: https://docs.microsoft.com/en-us/office365/admin/security-and-compliance/secure-your-business-data?view=o365-worldwide#6-stop-auto-forwarding-for-email