Allows the redirection of Printers/Drives/Ports for RDP connections. The recommended state for this setting is: Disabled. Rationale: In a security-sensitive environment, it is desirable to reduce the possible attack surface - preventing the redirection of COM, LPT and PnP ports will reduce the number of unexpected avenues for data exfiltration and/or malicious code transfer within an RDP session.
Solution
To establish the recommended configuration via GP, set the following UI path to: Disabled. Computer Configuration\Policies\Windows Settings\Security Settings\System Services\Remote Desktop Services UserMode Port Redirector Impact: Printers, drives and ports (COM, LPT, PnP, etc.) will not be allowed to be redirected inside RDP sessions. Default Value: Manual CIS Controls: Version 6 9.1 Limit Open Ports, Protocols, and Services Ensure that only ports, protocols, and services with validated business needs are running on each system. Version 7 9.2 Ensure Only Approved Ports, Protocols and Services Are Running Ensure that only network ports, protocols, and services listening on a system with validated business needs, are running on each system.