MC424901: Safe Attachments policy: Retire policy action ‘Replace’ for malware detections in attachments (Phase 1)

In Safe Attachments policies, ‘Replace’ is one of the actions that can be applied to messages that are found to contain malware. This action delivers only the message body without any of the original attachments. A replacement text attachment is added to the message to notify that the attachments were removed due to malware detection.

The ‘Replace’ action will be retired and will no longer be available in Safe Attachments policies. This retirement is implemented in two phases.

The first phase will start applying the ‘Block’ action behavior (quarantine the email) to existing policies with the ‘Replace’ action. This change will be applied automatically.

The second phase will remove the ‘Replace’ action selection from the Microsoft 365 Defender portal and related cmdlets. As part of this change, the ‘Replace’ action in any existing policies will be changed to the ‘Block’ action.

How this will affect your organization

Once this change is rolled out, any Safe Attachments policies with the ‘Replace’ action will not be honored and the action of ‘Block’ will apply automatically.

The phase 1 change will start rolling out in late-September 2022 and worldwide deployment will be complete by late-October 2022. For Government clouds, the deployment will start in mid-November 2022 and will be complete by mid-December 2022.

What you need to do to prepare

There are no alternatives to the ‘Replace’ action post retirement. Review and update Safe Attachments policies with the ‘Replace’ action to a different action (for example, ‘Block’ or ‘Dynamic Delivery’) before the phase 2 rollout.

Learn more

Please click Additional Information to learn more.

• SafeAttachments
• Safe Attachments policy settings

Message ID: MC424901
Published: 02 September 2022
Updated: 02 September 2022
Platform: Online, World tenant