Office 365 – Anti-spoofing protection to all Exchange Online organizations

If you are an existing E5/ATP customer, then this feature is already available to you and your current protection will not be impacted by this change. If you have previously disabled enhanced anti-spoofing in your anti-phishing policy or via customer support, you will not be impacted.

We continue to add additional updates to improve this filter, including a new spoof intelligence insight that is being rolled out to provide a better visibility and review experience.

This message is associated with Office 365 Roadmap ID: 32820.

[How does this affect me?]
After this change takes place, your organization will have access to enhanced anti-spoofing functionality that utilizes cloud intelligence, sender reputation and patterns to identify potentially malicious domain spoofing attempts. The new functionality works in conjunction with existing standards-based email authentication checks (DMARC/DKIM/SPF). Once this feature is enabled, messages that fail our extended implicit authentication checks will be automatically sent to the junk mail folder. You can use policies to customize these actions and turn this functionality on and off.

We are also updating the Get/Set-PhishFilterPolicy cmdlet to allow you to block/allow domains that are allowed to send spoofed mails, as well as the Get/Set-AntiphishPolicy cmdlet to let you modify the policies applied to spoofed messages. After the cmdlet changes, we will also roll out policy options in your Security and Compliance center.

If you have domain ‘allow’ or ‘safe’ sender policies or transport rules in place, they will not be impacted.

Policy options for these changes are now available via the Get/Set-AntiPhishPolicy cmdlet mentioned above, and will be available in your Security and Compliance center under threat management -> policy page -> anti-phishing, starting October 8, 2018. We’ll begin rolling this protection out and will be enforcing changes after October 15, 2018. We anticipate rollout completion in the following weeks.

[What do I need to do to prepare for this change?]
When we original communicated this change, we indicated that you would need to take action to disable enhanced anti-spoofing capabilities by September 21, 2018. If you have already taken action to disable this functionality, then you do not need to take further action. If you still wish to disable anti-spoofing capabilities, and have not yet done so, we have extended the deadline to disable to October 15, 2018. After October 15, we will begin rolling this feature out worldwide, and will enforce your existing settings.

Please click Additional Information to learn more about how anti-spoofing functionality can benefit your organization and to learn how to access settings to enable and disable this feature.