New-SafeAttachmentPolicy

The Action parameter specifies the action for the safe attachment policy. Valid values are:

• Allow: Deliver the message if malware is detected in the attachment and track scanning results. This value corresponds to Monitor for the Safe Attachments unknown malware response property of the policy in the Microsoft Defender portal.
• Block: Block the email message that contains the malware attachment. This is the default value.
• DynamicDelivery: Deliver the email message with a placeholder for each email attachment. The placeholder remains until a copy of the attachment is scanned and determined to be safe. For more information, see Dynamic Delivery in Safe Attachments policies.

The value of this parameter is meaningful only when the value of the Enable parameter is $true (the default value is $false).

To specify no action for the safe attachment policy (corresponds to the value Off for the Safe Attachments unknown malware response policy setting in the Defender portal), use the value $false for the Enable parameter.

The results of all actions are available in message trace.

The AdminDisplayName parameter specifies a description for the policy. If the value contains spaces, enclose the value in quotation marks (").

The Confirm switch specifies whether to show or hide the confirmation prompt. How this switch affects the cmdlet depends on if the cmdlet requires confirmation before proceeding.

• Destructive cmdlets (for example, Remove-* cmdlets) have a built-in pause that forces you to acknowledge the command before proceeding. For these cmdlets, you can skip the confirmation prompt by using this exact syntax: -Confirm:$false.
• Most other cmdlets (for example, New-* and Set-* cmdlets) don't have a built-in pause. For these cmdlets, specifying the Confirm switch without a value introduces a pause that forces you acknowledge the command before proceeding.

The Enable parameter works with the Action parameter to specify the action for the safe attachment policy. Valid values are:

• $true: The Action parameter specifies the action for the Safe Attachment policy.
• $false: This is the default value. Attachments are not scanned by Safe Attachments, regardless of the value of the Action parameter. This value corresponds to the Off selection for the Safe Attachments unknown malware response setting of the policy in the Microsoft Defender portal.

To enable or disable a complete Safe Attachments policy in the Microsoft Defender portal (the combination of the rule and the corresponding associated policy in PowerShell), use the Enable-SafeAttachmentRule or Disable-SafeAttachmentRule cmdlets.

The MakeBuiltInProtection switch is used for Built-in protection policy creation as part of Preset security policies. Don't use this switch yourself.

The Name parameter specifies a unique name for the safe attachment policy. If the value contains spaces, enclose the value in quotation marks (").

The QuarantineTag parameter specifies the quarantine policy that's used on messages that are quarantined as malware by Safe Attachments. You can use any value that uniquely identifies the quarantine policy. For example:

• Name
• Distinguished name (DN)
• GUID

Quarantine policies define what users are able to do to quarantined messages based on why the message was quarantined and quarantine notification settings. For more information about quarantine policies, see Quarantine policies.

If you don't use this parameter, the built-in quarantine policy named AdminOnlyAccessPolicy is used. This quarantine policy enforces the historical capabilities for messages that were quarantined as malware by Safe Attachments as described in the table here.

To view the list of available quarantine policies, run the following command: Get-QuarantinePolicy | Format-List Name,EndUser*,ESNEnabled.

The RecommendedPolicyType parameter is used for Standard and Strict policy creation as part of Preset security policies. Don't use this parameter yourself.

The Redirect parameter specifies whether to deliver messages to an alternate email address if malware is detected in an attachment. Valid values are:

• $true: Messages that contain malware attachments are delivered to the email address specified by the RedirectAddress parameter. This value is meaningful only when the value of the Action parameter is Allow.
• $false: Messages that contain malware attachments aren't delivered to another email address. This is the default value.

The RedirectAddress parameter specifies the destination email address to deliver messages if malware is detected in an attachment.

The value of this parameter is meaningful only when value of the Redirect parameter is $true and the value of the Action parameter is Allow.

The WhatIf switch simulates the actions of the command. You can use this switch to view the changes that would occur without actually applying those changes. You don't need to specify a value with this switch.