4.14 Ensure notifications for internal users sending malware is Enabled

Information

Setup the EOP malware filter to notify administrators if internal senders are blocked for sending malware.

Rationale:

This setting alerts administrators that an internal user sent a message that contained malware. This may indicate an account or machine compromise, that would need to be investigated.

Impact:

Notification of account with potential issues should not cause an impact to the user.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

To enable notifications for internal users sending malware, use the Microsoft 365 Admin Center:

Launch the Security.

Expand Threat Management then select Policy.

Select Anti-malware.

Change the setting Notify administrator about undelivered messages from internal senders to Always On and enter the email address of the administrator who should be notified under Administrator email address.

To check the setting from PowerShell, use the Exchange Online Module for PowerShell

Connect to Exchange Online by using the Connect-ExchangeOnline.

Run the following command:

set-MalwareFilterPolicy -Identity '{Identity Name}' -EnableInternalSenderAdminNotifications $True -InternalSenderAdminAddress {[email protected]}

See Also

https://workbench.cisecurity.org/files/3433