Excluding removable USB-drives from automatic encryption

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This week a short blog post to address a scenario that’s been challenging for a while. That scenario is around removable USB-drives and automatic encryption. When organizations have configured that removable drives require encryption, that introduces challenges with storage built into specialized devices like video cameras, voice recorders, conferencing systems, medical devices and many more. That would also require that type of storage to be required, when read access wasn’t sufficient. That, however, would often cause more problems than solutions. To address that challenge, Microsoft has introduced a new policy. That policy can be used to create an exclusion list of devices for which the user will not be prompted for encryption. Even when encryption of removable drives is required. This post will introduce that new policy setting and will walk through the configuration of that policy setting. This post will end with the user experience.

Note: The configuration to require encryption of removable drives is referring to using the RemovableDrivesRequireEncryption policy setting when using MDM, or to using the Deny write access to removable drives not protected by BitLocker when using Group Policy.

Important: This post relies on functionality that is at the moment of writing only available in Windows 11 Insider Preview Builds in the Dev Channel. Setting is available starting with Windows 11 Insider Preview Build 22579.

Creating custom device configuration policy to exclude removable drives

Starting with Windows 11 Insider Preview Build 22579, Microsoft introduced a new policy setting as part of the BitLocker CSP. That new policy setting is RemovableDrivesExcludedFromEncryption. A nice self explanatory setting that can be used exclude removable drives from the encryption requirement. That setting requires a String data type value of the Hardware ID of the removable drive. The Hardware ID can be found in the Details tab in the Properties of a device in the Device Manager. When multiple drives should be listed, the different values can be separated by a comma. The following nine steps walk through the process of adding this new policy setting in Microsoft Intune and distributing it to Windows 11 devices.

  1. Open the Microsoft Endpoint Manager admin center portal navigate to Devices > Windows > Configuration profiles
  2. On the Windows | Configuration profiles blade, click Create profile to open the Create a profile page
  3. On the Create a profile page, provide the following information and click Create
  • Platform: Select Windows 10 and later as value
  • Profile type: Select Templates as value
  • Template name: Select Custom as value
  1. On the Basics page, provide a unique Name to distinguish the profile from other custom profiles and click Next
  2. On the Configuration settings page (as shown below in Figure 1), click Add to open the Add Row page. On the Add Row page, provide the following information and click Add (and click Next back on the Configuration settings page)
  • Name: Provide a valid name for the OMA-URI setting as value
  • Description: (Optional) Provide a valid description for the OMA-URI setting as value
  • OMA-URI: Provide ./Device/Vendor/MSFT/BitLocker/RemovableDrivesExcludedFromEncryption as value
  • Data type: Select String as value
  • Value: Provide the HardwareID of the USB-drive as value
Figure 1: Overview of the custom setting for excluding removable USB-drives

Note: The configuration in Figure 1 is using the Hardware ID of a SanDisk removable USB-drive as an example.

  1. On the Scope tags page, configure the applicable scopes and click Next
  2. On the Assignments page, configure the assignment and click Next
  3. On the Applicability rules page, configure the applicability rules (think about the existence of this setting for only the specific Windows Insider build and later) and click Next
  4. On the Review + create page, verify the configuration and click Create

Note: The expectation is that this policy setting will, in time, become directly configurable within the Microsoft Endpoint Manager admin center, as part of one of the existing configuration templates (or the Settings Catalog).

User experience with excluded removable drives

When looking at the user experience, the most important part is that the removable USB-drive works for the user. That can be shown by physically insertting a removable USB-drive in to the device. That, however, is impossible to show in a screenshot. What can be shown is a succesful exclusion in the Event Viewer. The System log contains Event ID 24701 that provides information about the exclusion, once the user inserts the removable USB-drive. That event revers to the volume (as shown with number 1 and 3 in Figure 2) and the specific Hardware ID (as shown with number 2 in Figure 2). The Hardware ID relates to the configured Hardware ID in the created configuration.

Figure 2: Overview of the user experience with an excluded removable USB-drive

More information

For more information about the new setting to exclude removable USB-drives, refer to the following docs.

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32 thoughts on “Excluding removable USB-drives from automatic encryption”

  1. Hi Peter, thank you for yet another clear instruction of new functionality coming from Microsoft. Your blogs are always interesting to read. I do have a couple of questions on this if you could help.

    The first one is easy, do you know if the settings will be back-versioned to Windows 10?

    The second one is an odd one, your instructions state to put the HardwareID of the device into the Value, you are testing with “USBSTOR\DiskSanDisk_Cruzer_Edge____1.20”, if, for example I plugged in a new Cruze Edge USB and the version was____1.21, could I change the original string to “USBSTOR\DiskSanDisk_Cruzer_Edge____1” to incorporate both or would I need to create a new config?

    Reply

    • Hi Rob,
      There is not a lot of documentation around this setting yet, but at this moment it’s Windows 11 only. Besides that, I think it’s not allowing variables and it would require a full string of the HardwareID.
      Regards, Peter

      Reply

  2. Good Morning guys,

    is it possible to exclude an existing user from being encrypted by their USB while using bitlocker in intunes?
    Thanks!

    Regards, Armin

    Reply

  3. Hi Peter, I need your guidance in this. Do we have option to block automatic encryption for all removable drives/usb irrespective of model .If yes, how this can be accomplished ?

    Reply

  4. Hi Peter,
    Thank you very much, awesome read.
    Even better than the first-party-knowledge-base!

    is there any way to integrate this feature into classic Microsoft Endpoint Configuration Manager (the on-prem one)?

    Thanks again, Christoph.

    Reply

  5. Hi Peter,

    How do i add multiple USBs?

    If i add one it works perfectly fine, however when i add a second usb it doesn’t work?

    Can you assist?

    Kind regards,
    Jack

    Reply

  6. I have tried this and it is still only Windows 11. But there is a serious problem with the implementation. The HardwareID you have to put in is not unique to a specific USB drive. It is the same value for all drives of the same type from the same manufacturer. I bought several of the same USB drives. I needed to bypass the encryption for write access to one of them. But this bypassed for all of them.

    Reply

      • Hi Peter

        It is specific to a vendor. Here are Hardware IDs from some of our USB drives:

        USBSTOR\DiskSanDisk_Ultra___________1.00
        USBSTOR\DiskSanDisk_Cruzer_Blade____1.00
        USBSTOR\DiskSony____Storage_Media___0100
        USBSTOR\DiskImation_Classic_________PMAP

        The ID includes the vendor name.

        According to Microsoft, “A hardware ID is a vendor-defined identification string that Windows uses to match a device to a driver package. A hardware ID identifies what a device is to some level of specificity and is indicating that any driver package that declares it can work with a device that has that ID can work with this device for some degree of functionality.”

        So it is really up to the vendor to determine how many different types of their brand of USB drive would have the same Hardware ID.

        This does not work well in our scenario. We want the general rule to be that removable storage is encrypted as it could store personal, private or confidential information. But sometimes we need to be able to write to a USB drive that will then be used in a situation where having it Bitlocker encrypted is not appropriate.

        What I would really like to be able to do is provide an exception list based on the serial number of the USB drive. If you use the following command, you can get the serial number of the drives in a system:

        wmic diskdrive get Model, Name, InterfaceType, SerialNumber

        The output from this command for my SanDisk Ultra USB drive is:
        InterfaceType : USB
        Model: SanDisk Ultra USB Device
        Name: \\.\PHYSICALDRIVE3
        SerialNumber: 4C530001291026121572

        Regards
        David

        Reply

    • I have implemented this combined with ASR Reusable Settings (Scenario 1 from: https://techcommunity.microsoft.com/blog/coreinfrastructureandsecurityblog/mde-device-control-%E2%80%93-leveraging-reusable-settings-in-intune/3905072)

      For the ASR settings I am using InstancePathId which seems to be unique.
      In my testing was able to:
      1 – Restrict write to any removable media
      2 – Allow write to specified removable media with encryption
      3 – Allow write to specified removable media without encryption

      Reply

  7. Is it possible to retrieve a list with hardware ID’s with KQL. In other words – is it possible to retrieve the devices that ‘hit’ the Bitlocker to go (removable devices) possible with the devicename and the primary user. I don’t want to bother people in the org to investigate by themself which specific USB device is used to make the exceptions (if allowed)

    Reply

  8. Hello Peter,
    We have a user based policy from Intune to enforce bitlocker encryption on USB for all users.
    However, I would like to try out your steps on a user who has a need to use a specific USB device which is already encrypted by a third party vendor, I wanted to make sure the user still gets bitlocker prompt whenever user insert any other USBs.

    Question: Where do I apply your policy? to user system?

    Thanks in advance.

    Solu E

    Reply

  9. Hello, I have tried this settings, but the configuration apears in the intune as not applicable (I deployed it to win11 machine) The main bitlocker policy is set by Intune, in the Endpoint security section – it can be in conflict with this settings?
    thanks

    Reply

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