Enable copy paste Remote Desktop Windows Server 2016

Configuring RDS Clipboard Redirection settings is a fundamental step in the hardening project. Hardening can be a painful procedure. If youre reading this article, you probably already know it. Endless hours, and resources are invested in this process. However, despite the efforts, hardening often causes downtime. In fact, over 60% of IT professionals report theyve experienced downtime while trying to harden their infrastructure.

After years of hardening using the traditional manual tools, we concluded that using hardening automation tools is essential for achieving a successful hardening project and a good compliance posture. Learn more about server hardening automation.

This article aims to provide basic information regarding the Clipboard Redirection setting, which enables the copy past function in remote desktop. Once youll decide this settings desired value, make sure you test it, to fully understand what will be its impact on your production. This is highly important since you dont want it to result in damage to production.

In this article youll learn:

What is Clipboard Redirection:

The Do not allow Clipboard redirection setting specifies whether to prevent the sharing of clipboard contents [clipboard redirection] between a remote computer and a client computer during a Remote Desktop Services session. By disabling this setting you wont be able to initiate a copy past action in a remote desktop session.

RDP clipboard vulnerability

You can use this setting to prevent users from redirecting clipboard data to and from the remote computer and the local computer.

*If the status is set to Enabled, users cannot redirect clipboard data.

*When Disabled, Remote Desktop Services always allows clipboard redirection [this is the default behavior].

*If the status is set to Not Configured, clipboard redirection is not specified at the Group Policy level. However, an administrator can still disable clipboard redirection using the Remote Desktop Session Host Configuration tool.

Clipboard Redirection Potential Vulnerability:

Microsofts clipboard sharing channel supports several data formats such as CF_HDROP, which is responsible for the Copy & Paste feature. When used, it allows us to simply copy a group of files from one computer to the other. If the client itself fails to prevent malicious files from entering his computer via this feature, he could be vulnerable to a path traversal attack. The server can then drop malicious files in arbitrary paths on the clients computer. In other words, the clients approval of the files is the only thing protecting him from this vulnerability. Considering the fact that the client doesnt even need to verify the received files coming from the RDP server, it is almost impossible to detect the attack.

How to Mitigate Clipboard Redirection Vulnerability:

attackers commonly use RDP for malicious activity, therefore it is recommended to configure the Remote Desktop Server to only allow required tasks. If youve decided that some users do need the clipboard function enabled, it is recommended to segment the LANs that have RDP clipboard enabled, so they can be tracked.

How to Secure Remote Desktop The Complete Guide

The Potential Impact of Clipboard Redirection Disabling:

As simple as it sounds, remote users wont be able to use the clipboard functionality. That may lead to damage in production for applications that rely on this ability.

Vulnerability Severity:

Critical

CalComs RECOMMENDED VALUE:

Enable

HOW TO CONFIGURE Clipboard Redirection:

Windows 2016 server:

In Windows 2016, these settings are controlled within Group Policy.

1. Launch msc.
2. Navigate to Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host.
3. Ensure Do not allow Clipboard redirection is set to Enabled.

Windows 2012 server:

1. Open Server Manager.
2. Select Remote Desktop Services.
3. Select Collections.
4. Select Tasks, then choose Edit Properties.
5. Under the Client Settings tab, ensure the Clipboard and Drive are disabled.

Windows 2008 server:

1. Launch Remote Desktop Session Host Configuration from the server.
2. Under Connections, right-click the connection and select Properties.
3. Select the Client Settings tab, and make sure the Clipboard box is checked. Ifyou dont want to allow copying and pasting of files, make sure the Drive selectionis checked. ClickOKwhen done.

Server Hardening Automation:

Since the testing process is complex and highly prove to human mistakes, we recommend automating the entire hardening process. CalCom offers a fully automated server hardening tool CHS. CHSs unique ability to learn your network eliminates the need to perform lab testing while ensuring zero outages to your production environment. CHS will allow you to implement your policy directly on your production servers, hassle-free.