check before: 2022-05-27


Defender, Defender for Office 365, Exchange, Microsoft 365 Defender, Microsoft 365 suite, Microsoft Defender for Office 365


Germany, Online, US Instances, Web, World tenant


In development

Change type:

Feature update, Admin impact




In anti-malware policies, you can select specific file types to identify as malware using the common attachment filter. Any email message with attachments of these specific file types will be handled per the policy settings. You can configure this specific list of file types by selecting them from the pre-defined list in the policy properties in the Microsoft 365 Defender portal or by manually adding your own (custom) file types using the power shell Set-MalwareFilterPolicy cmdlet in Exchange Online PowerShell.

Based on internal research and best practices guidelines from industry and other organizations, we are updating the list of file types that are available for selection. Currently, there are 95+ file types in the list, of which 13 are pre-selected by default in the common attachment filter settings. We are expanding this list to cover over 200 file types, of which over 50 are selected by default.

After rollout, this new expanded list along with the default selection will automatically apply to:

Any new anti-malware policies that you create
The default anti-malware policy
The file selections in your existing anti-malware policies (enabled or not) will be retained and will not be updated automatically. You will need to manually update your existing policies with the recommended list of default file types (see below).

This message is associated with Microsoft 365 Roadmap ID 85611

[When this will happen:]

Starting mid-June and completion of deployment by late July

Change Category:


Release Phase:
General Availability



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