What is Remote Desktop Protocol (RDP )?

Remote Desktop Protocol: What is it? How to protect it?
 
The vulnerabilities found in Remote Desktop Protocol (RDP) have attracted everyone's attention. Dan Kaminsky, a well-known network security expert, recently said that RDP is currently being used in more than 5 million Internet endpoints. As you can imagine, if enterprises do not properly protect RDP, network and endpoint security will be seriously threatened.
 
In this article, we will briefly discuss what RDP is, why we need RDP, and the most common way it is used for enterprise endpoints. Then, we will discuss how enterprises can ensure the secure use of RDP, or, when appropriate, how to ensure that it is not used.
 
What is RDP?
 
Remote Desktop Protocol is a proprietary protocol created by Microsoft. It allows system users to connect to a remote system through a graphical user interface. By default, the client agent of this protocol is built in Microsoft's operating system, but can also be installed in non-Microsoft operating systems, such as Apple's operating system and Linux of different versions, it can even be installed in a mobile operating system, such as Android.
 
The RDP server is installed on the Microsoft operating system and receives requests from the client proxy. The diagram of the published application or remote access to the system itself is displayed. By default, the system listens to connection requests from clients through RDP on port 3389.
 
What are the most common methods of RDP in enterprises?
 
Generally, RDP or terminal service session is configured on the server that needs to be connected by a distributed client machine. It can be used for management, remote access, or publishing applications for central use. This protocol is also often used by the desktop administrator to remotely access the user system to assist in troubleshooting. If RDP is not correctly configured, this type of feature poses a threat to the enterprise because unauthorized visitors can access key enterprise systems.
 
How to Protect RDP
 
Now we know what RDP is and how enterprises use it. The following are some methods to protect RDP:
 
• Confirm that 128-bit encryption is used between the client and the server; 128-bit encryption allows more powerful and less easily cracked keys. By default, RDP connections attempt to use 128-bit encryption, but if it cannot use 128-bit encryption, the client may return to 64-bit encryption. To ensure that the system does not fall back to lower-level encryption, the administrator can configure the Group Policy object (GPO) to conform to their respective standard encryption levels. We recommend that you enable "advanced" encryption.
 
• If you need to access the system through an external network, you should not open the port so that anyone can abuse it. We recommend that you configure the VPN as the return network and then use RDP. A better solution is to create a Remote Desktop gateway that allows remote connection between HTTPS and RDP to create a safer encrypted connection to connect the endpoint. We recommend that you enable the RDP port 3389 of the peripheral network in both methods.
 
• By using a newer version of windows, the administrator can enable network-level authentication (NLA) as an additional verification before establishing a connection to the RDP host server. This frees authentication from the system and consumes less resources. This also helps reduce potential DoS attacks that are implemented through brute-force cracking. NLA acts as a buffer to prevent attackers from using access requests to block RDP host servers.
 
• By default, the RDP host system listens to connection requests from RDP clients on port 3389. We can change the listening port of the RDP service to prevent malicious software or attackers from scanning the system to find the RDP port 3389 to protect network security. However, this "Fuzzy Security" method may cause errors and negligence. You can change the port, but you need a good reason.