Conditional Access Block Download Attachment

Evangelos Rizos 1 Reputation point
2021-03-30T10:19:18.71+00:00

Hello , I trying for a few days to enable correct a Conditional Access Policy that blocks attachments to download.

I managed to block attachment in owa but still have the option to save it to one drive.

Image

In windows i have the option to save it locally or in OneDrive. In mobile app i have the option to save it to device.

82746-outlook-windows.png

The conditional access policy

82772-policy.png

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9 answers

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  1. Andy David - MVP 142.2K Reputation points MVP
    2021-03-30T11:39:32.597+00:00

    You need to enable this on the Sharepoint side which will create the Conditional Access policy
    https://learn.microsoft.com/en-us/sharepoint/control-access-from-unmanaged-devices

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  2. Evangelos Rizos 1 Reputation point
    2021-03-30T12:41:50.163+00:00

    ok that solved the problem in owa but in device still have the option to download it and in outlook windows too.
    82734-device.jpg

    82736-image-2021-03-30-154142.png

  3. KyleXu-MSFT 26,211 Reputation points
    2021-03-31T01:54:02.117+00:00

    @Evangelos Rizos

    Try to use “Set-ActiveSyncMailboxPolicy” command to block attachment from downloading:
    82935-qa-kyle-09-52-28.png

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  4. Evangelos Rizos 1 Reputation point
    2021-03-31T11:16:08.473+00:00

    Hello and thank you for your answers!!!

    I have already done this procedure.83279-image-2021-03-31-141558.png

    Ok maybe i don't ask the right questions... now I'm confused.
    the question is what is the right procedure to block attachments from any device (web, windows app, mobile app ) ?

    Thank you again.

  5. Andy David - MVP 142.2K Reputation points MVP
    2021-03-31T11:50:15.383+00:00

    Hi, thats not the correct setting if using Conditional Access.

    If you want to block using OWA, follow:
    https://petri.com/conditional-access-blocks-office-365-downloads

    If you want block on mobile devices, look at Cloud App Security:
    https://learn.microsoft.com/en-us/cloud-app-security/use-case-proxy-block-session-aad

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