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7 Replies

  • rajatm's avatar
    rajatm
    Copper Contributor

    MCAS cannot enforce session policies on desktop/native apps. Session policies and controls (including block downloads) are limited to browser sessions only. This is documented at: https://docs.microsoft.com/en-us/cloud-app-security/session-policy-aad

     

    For native/desktop apps, MCAS can allow or block access completely using a CAS Access policy but this does not allow granular control over activities.

     

    A typical implementation in a scenario where one wants to limit downloading of files for users on non-compliant or non-hybrid joined machines, is to have a CA policy in AAD conditional access to forward sessions to CAS (using the 'use custom policy' option) and a CAS access policy to block desktop/native apps (and force users to web-apps) and a CAS session policy to block/control downloads in these web-app sessions.

    • gd2020's avatar
      gd2020
      Copper Contributor

      Hi rajatm , In your suggestion below can you explain how i create an CAS policy to block native apps and force users to use the Web app  "CAS access policy to block desktop/native apps (and force users to web-apps) and a CAS session policy to block/control downloads in these web-app sessions."

       

      I have an access control policy for native client as follows:

      ACCESS POLICY

      Device+ tag+ does not equal =Intune Compliant , Hybrid Compliant. 

      App=Microsoft teams

      User Agent tag =Native Client 

      USer +NAme = (User) 

       

      Session Policy 

      - Control file downloads with Inspection

      app=Microsoft teams

      USer +Name =(User) 

      Device+tag=HybridAzure Ad joined,Intune compliant

       

      cant seem to get users on a Non Supported device be stopped from downloading files from teams.

       

       

       

      • rajatm's avatar
        rajatm
        Copper Contributor

        hello gd2020 , you should add a 'client app' == 'Mobile or desktop' filter to the access policy. without this filter, access policies only apply to browsers. this is documented at: https://docs.microsoft.com/en-us/cloud-app-security/proxy-intro-aad#access-controls . this access policy should then block users from being able to sign-in to the Teams desktop app. 

  • Hello,

    You can block downloads in SharePoint Online and Ondrive ,

    -Conditional Access Policy 

     

    Control access from unmanaged devices:

    https://docs.microsoft.com/en-us/sharepoint/control-access-from-unmanaged-devices?redirectSourcePath=%252fen-us%252farticle%252fcontrol-access-from-unmanaged-devices-5ae550c4-bd20-4257-847b-5c20fb053622

     

    Microsoft recommends you protect content in SharePoint sites with sensitive and highly-regulated content with device access controls. You do this by creating a policy that specifies the level of protection and the sites to apply the protection to.

    • Sensitive sites: Allow browser-only access. This prevents users from editing and downloading files.
    • Highly regulated sites: Block access from unmanaged devices.

    See "Block or limit access to specific SharePoint site collections or OneDrive accounts" in this article: Control access from unmanaged devices.

     

     

    George Smyrlis 

    • Lassaad 

       

      Great answer.  Also worth pointing out that Conditional Access requires a minimum of Azure AD Premium P1 licence, and to use session controls you will also need to be licensed for Cloud App Security.

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