I guess it’s time for the sixth part of the Endpoint Security Series. This time, I will walk you through Microsoft Defender Device Control, how to configure it in Intune, and how it works.

1. Some Information about Device control 

Microsoft Defender for Endpoints has a cool feature protecting devices against data loss. This feature provides a layered approach to secure removable hardware like external hard drives. Of course, this feature couldn’t have any other name than Windows Defender Device Control.

When using Device Control, you could prevent users from installing specific hardware on the devices or prevent removable storage from being used! 

The only prerequisite? It would be best to ensure that Microsoft Defender for Endpoints is enabled and active. If you have configured another AV, Microsoft Defender will be running in passive mode, and Device Control will probably not work

2. How to Configure Device Control in Intune 

Like always, open Intune and Click on Endpoint Security –> Attack Surface Reduction to create a new policy.

I am going to split this first one up. Because the first part is sometimes difficult to understand and configure.  The second part about allowing removable storage speaks for itself. 

Allowing / Blocking Hardware

These settings allow you to create allow lists or deny lists based on hardware IDs or specific device GUID allows lists (and deny lists). This allows us to secure the environment based on the specific hardware allowed to connect.  Configuring a block policy will apply to the device, so even if your end-users are configured as local administrators, it will be blocked.

Block / Allow Hardware Device installation by device identifiers 

Specific Hardware IDs you configure in this policy are forbidden and blocked from being installed. 

PLEASE NOTE: The device ID isn’t the PnP ID but the Hardware ID 

*How to find the Device/Hardware Id with the device manager 

*How to find the Device/Hardware Id with PowerShell? 

Get-WmiObject Win32_PNPEntity | select name,hardwareid | sort-object hardwareid | Get-Unique -asstring  |fl 

Block/ Allow  Hardware device installation by setup classes: 

Device GUIDs entered here are prohibited from being installed. Prevent policies have higher priority over allowed policies. If a device class GUID is configured for both allow and disallow policies, the devices will not be allowed to install. 

*How to find the Class GUID with the device manager 

While looking at the device Class GUIDES, I realized I had also written a blog on this topic some time ago. The blog will show you how to allow normal users to install printer drivers independently.

*How to find the Class GUID with PowerShell? 

Get-WmiObject Win32_PNPEntity | select name,classguid | sort-object classguid | Get-Unique -asstring  |fl 

Block/ Allow  Hardware device installation by  device instance identifiers: 

A device instance ID is a system-supplied device identification string that uniquely identifies a device in the system. The Plug and Play manager assigns a device instance ID to each device node  in a system’s device tree

*How to find the Device instance ID with the Device Manager 

*How to find the Device instance ID with PowerShell? 

Get-WmiObject Win32_PNPEntity | select name,deviceid | sort-object deviceeid | Get-Unique -asstring  |fl 

Configuring USB storage media and Bluetooth  

This one is more clear than blocking or allowing the installation of hardware. Let’s take a look at some of the policies. 

All of the settings above allow us to control what devices can connect to our computers. In the sample above, I am making sure people can still use Removable Storage, but I am preventing write access. Setting up a policy like this will ensure that your Company data can’t be copied to a USB stick. 

I am also allowing Bluetooth, but like the removable storage, I am restricting its use. 

3. Results of Blocking specific hardware! 

When configuring an Endpoint Security device control policy to block hardware device installation by device identifier, we need to know what happens to the client. 

First, let’s open the device manager, we will notice the hardware couldn’t be installed. 

Error Code 1:  The installation of this device is blocked by a system policy 

You will also get a nice toast message with the same message above. 

And of course, the removable storage device in this example is not accessible!

4. Results of preventing Write Access Removable Storage  

Now that we have seen what happens when you totally block all access to removable storage, let’s see what happens when you block the possibility of writing data to removable storage. 

The only way to test it is to attach a USB removable storage device and try to create a folder or copy some data to it. You will be prompted with this error: ACCESS DENIED!

5. Deploy printer protection on Windows

Today a new method for printer protection was released. When discussing Device Control, controlling which printer may be used for printing is great!

Please make sure you have applied for the correct license!

• Microsoft 365 E3 for functionality/policy deployment
• Microsoft 365 E5 for reporting

The new printer protection feature allows you to block users from printing via a non-corporate network printer or non-approved USB printer. This adds an additional layer of security and data protection for work-from-home and remote work scenarios.

So, how do we configure this?

Before we start we need to make some hard choices, are you going to deploy it to the machine or user context? Now we made a choice: create two CSPs and configure the values as I show below

MACHINE CONTEXT

*Block printing from non-approved printers

OMA-URI: ./Vendor/MSFT/Policy/Config/Printers/EnableDeviceControl
Value:<enabled/>

*Define the approved USB printers

OMA-URI: ./Vendor/MSFT/Policy/Config/Printers/ApprovedUsbPrintDevices
Value: <enabled/><data id=”ApprovedUsbPrintDevices_List” value=”03F0/8117,03F0/8217″/>

USER CONTEXT

*Block printing from non approved printers

OMA-URI: ./Vendor/MSFT/Policy/Config/Printers/EnableDeviceControlUser
Value:<enabled/>

*Define the approved USB printers

OMA-URI: ./Vendor/MSFT/Policy/Config/Printers/ApprovedUsbPrintDevicesUser

Value: <enabled/><data id=”ApprovedUsbPrintDevices_List” value=”03F0/8117,03F0/8217″/>

Wondering what the 03f0/8117 stands for? The VID/PID. Could you open the device manager to get them?

When you don’t want to take a look in the device manager to find them, please visit this Device Hunt website

USB\VID_03F0 – HP, Inc | Device Hunt

Of course, the results when you plug in your private USB printing device and want to print something. You will notice the print job is sent to the spooler but also immediately removed!

Open the event log and open the Print Service event log

When looking and translating the nice dutch text: It will be blocked because of some printer restrictions. The USB printer is not on the list of allowed devices!

6. Digger deeper 

When you want to monitor if the restrictions are configured on the device itself, its best to open the local registry and open this key 

You will notice all the settings you configured in Intune are deployed to these registry keys 

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\DeviceInstall 

When looking at this key,  you will notice that there is a difference between blocking Hardware ID’s 

And when you are blocking Device Instance ID’s 

But how do these keys end up in here? Just like all settings in Intune, A CSP is responsible for it. SO let’s take a look at which one. Open this registry key to start digging. 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PolicyManager\current\device\ 

Do you notice the ADMXInstanceData key? Let’s open that one now. 

It has the same JSON content in it configured which you would do with a CSP. 

OMA-URI:./Device/Vendor/MSFT/Policy/Config/DeviceInstallation/PreventInstallationOfMatchingDeviceInstanceIDs 
DataType: String 

7. Logging  

Here comes the discussion…. Are we going to block removable storage, limit its use, or just allow it? 

For each choice you make, you must ensure you don’t set and forget. You really need to know when someone is trying to attach a new removable storage device.  So you need to monitor it, so go open your event log and go take a look at the Kernel-PnP event log

But what to do, when you are not blocking removable storage? Of course, you want to ensure you are logging all those events. How will we ensure we are notified when someone successfully copies a file? MCAS! This is the way! 

Like always, I have done a blog about this subject some time ago. Go out and read it if you are interested!

8. Removing/ Changing the policy 

Removing the whole policy or removing the assignment in Intune will also ensure the settings are removed from the device!  

But beware, if you are changing an existing policy and you only remove the Hardware IDs like the ones below, it will not remove the settings from the client.

You will need to change the: Block hardware device installation by device identifiers to: not configured 

And within a few minutes after syncing the device in Intune the whole register DenyDevicesIDS key is deleted 

Conclusion 

It really depends on the organization you work for if you need to limit, block, or allow and log these types of actions. It’s a good thing Microsoft has all the options available for us to start dancing and do our jobs!  

If you want to read the previous Endpoint Security blogs:

Endpoint Security Series – Call4Cloud

And if you are not interested in the endpoint security blogs I still got some other blogs for you!

• Fixing Time Zone Issues in Windows Autopilot
• Mastering Device Compliance: The Game-Changing Tpm-PreAttestationHealthCheck in Windows 24H2
• Fix Subscription Activation by automatically Removing Secondary Work or School Accounts.
• Autopilot Device Preparation (AVP2/AP-DPP): Hiding the Privacy Settings
• The Incredible story of using the Windows Performance Recorder to troubleshoot your Enrollments.