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Microsoft Security Community Blog
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Admin control for attachments now available in Office 365 Message Encryption

Caroline Shin's avatar
Caroline Shin
Iron Contributor
Jun 13, 2018

EDITORS NOTE 1/3/2019

We have updated the blog to reflect that we've expanded the ability to control if Office attachments are protected for recipients inside Office 365 - previously this was only supported for non-Office 365 users. Changes are reflected below in the blog. 

 

Summary

Administrators can now control whether Office attachments are protected for recipients inside and outside of Office 365 when the Encrypt-Only template is used.  This was a key ask from Office 365 Message Encryption customers and is now available as a tenant-level setting.

 

Background

 

We have now made it possible for administrators to control how Encrypt-Only behaves for attachments. By default, when a user sends an email and attachments using Encrypt-only, the Office attachments are also protected with Encrypt-Only permissions and that encryption persists throughout lifecycle of the content. To provide more flexible controls for recipients, organizations can control if recipients have unrestricted permissions on the attachment or not for Encrypt-Only emails. For example, one scenario this is valued is when a doctor shares a protected attachment to her patient, and the patient wants to share this with his family, the attachment is no longer encrypted so they can open the attachment without any additional steps.

 

What is available 

 

Admins can control whether attachments have unrestricted permissions for Encrypt-Only emails. Details on implementing the settings are below.

 

When the recipient signs-in to the Office 365 Message Encryption portal, they can preview attachments as before. 

 

 

  

If the control to unrestrict the attachment is enabled, the document will be decrypted and the recipient will be able to view it normally. Additionally, the content will remain decrypted and unrestricted unless additional protections are applied.

 

 

Scope

 

This setting is available for the Encrypt-only template and not for the Do Not Forward or Custom templates.

 

It’s enforced at the tenant level.

 

How to control the setting

 

To manage whether to allow recipients to download Encrypt-only attachments without encryption, follow these steps:

 

Connect to Exchange Online Using Remote PowerShell (see https://aka.ms/exopowershell)

Run the Set-IRMConfiguration cmdlet with the DecryptAttachmentForEncryptOnly parameter as follows:

 

Set-IRMConfiguration - DecryptAttachmentForEncryptOnly <$true|$false>

 

For example, to allow download of attachments without protection for Encrypt-only:

Set-IRMConfiguration - DecryptAttachmentForEncryptOnly $true

 

If you decide that you want to revert the setting and keep attachments protected even after download:

Set-IRMConfiguration - DecryptAttachmentForEncryptOnly $false

 

Please note, as of 12/13/18, we have deprecated  DecryptAttachmentFromPortal. It will continue working for existing customers who have run the old cmdlet but new customers should start using the new cmdlet (DecryptAttachmentForEncryptOnly) updated above.

 

Additional Resources

 

This was a key ask from organizations that had a broad set of scenarios which requires email recipients to "own" the attachment by unrestricting permissions on the attachment. We hope this additional control can provide more flexibility in collaborating on protected content for all users. Your feedback matters- leave us a comment below or go to uservoice and submit your feedback/vote! 

 

For additional resources on Office 365 Message Encryption - you can find them below:

 

 

 

Updated May 11, 2021
Version 8.0

28 Comments

  • Salah Ahmed's avatar
    Salah Ahmed
    Iron Contributor

    Scoped RMS templates in ETRs is coming very soon. Though can't give a public eta yet.

  • Hi When will you add support for scoped RMS templates in Exchange transport rules ? We cannot move to Azure based RMS due to that.
  • Salah Ahmed's avatar
    Salah Ahmed
    Iron Contributor

    This is unexpected. If anyone else runs into this issue, they should open a support ticket.

  • P Roby's avatar
    P Roby
    Copper Contributor

    This what I receive 

     

    A parameter cannot be found that matches parameter name 'DecryptAttachmentFromPortal'.
    + CategoryInfo : InvalidArgument: (:) [Set-IRMConfiguration], ParameterBindingException
    + FullyQualifiedErrorId : NamedParameterNotFound,Set-IRMConfiguration
    + PSComputerName : outlook.office365.com

  • Salah Ahmed's avatar
    Salah Ahmed
    Iron Contributor

    @P Roby, the feature is fully rolled out.

     

    @Vamsi the feature allows download without encryption from the OME portal for any recipient. It doesn't matter which identity forwarded the email to the recipient.

  • P Roby's avatar
    P Roby
    Copper Contributor

    Desperately need this feature! When will it complete rollout to our tenancy?

  • Andrew Woo's avatar
    Andrew Woo
    Brass Contributor

    It is a welcoming feature, but how reliable is it, we still have to test it out

     

    Comment edited to add the following sentence.

    Please make thing simple....Not powershell please.

  • Its a great announcement after Encrypt feature, appreciate your continuous efforts to make customers flexible to use 'Encrypt' feature.

     

    I have couple of queries regarding this,

    1. If a non-O365 user forwards the email to O365 user will the document remains encrypted for O365 user? 

    2. If a O365 user (who are not on the earlier version - 1804 of Outlook) forwards the email to non-O365 user from OME portal, will the attachment gets decrypted for non-O365 users?