18.10.58.3.3.1 Ensure 'Do not allow COM port redirection' is set to 'Enabled'

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Information

This policy setting specifies whether to prevent the redirection of data to client COM ports from the remote computer in a Remote Desktop Services session.

The recommended state for this setting is: Enabled.

Rationale:

In a more security-sensitive environment, it is desirable to reduce the possible attack surface. The need for COM port redirection within a Remote Desktop session is very rare, so makes sense to reduce the number of unexpected avenues for data exfiltration and/or malicious code transfer.

Impact:

Users in a Remote Desktop Services session will not be able to redirect server data to local (client) COM ports.

Solution

To establish the recommended configuration, set the following Device Configuration Policy to Enabled:

To access the Device Configuration Policy from the Intune Home page:

Click Devices

Click Configuration profiles

Click Create profile

Select the platform (Windows 10 and later)

Select the profile (Administrative Templates)

Click Create

Enter a Name

Click Next

Configure the following Setting

Path: Computer Configuration\Windows Components\Remote Desktop Services\Remote Desktop Session Host\Device and Resource Redirection
Setting Name: Do not allow COM port redirection
Configuration: Enabled

Select OK

Continue through the Wizard to complete the creation of the profile (profile assignments, applicability etc.)

Note: More than one configuration setting from each of the Configuration profiles (ex: Administrative Templates, Custom etc.) can be added to each Device Configuration Policy.

Default Value:

Disabled. (Remote Desktop Services allows COM port redirection.)

See Also

https://workbench.cisecurity.org/benchmarks/14664