What is RDP and how to protect it from vulnerabilities?

The boom in remote work has driven the massive use of tools that allow remote access to computers and servers, with Remote Desktop Protocol (RDP) being one of the most widely used in corporate environments. This function, integrated into Windows systems, facilitates remote connectivity and technical support without the need to be physically on site.

However, as adoption grows, so do the associated risks. Many organizations are not fully aware that, if not properly configured, RDP can become a direct avenue for cyber attacks. Vulnerabilities in its security have already been exploited by ransomware groups and cybercriminals around the world. The key is to understand how RDP works, identify its weaknesses and implement the necessary measures to close them before it is too late.

What is RDP?

RDP, which stands for Remote Desktop Protocol, is a tool that allows you to connect to another computer and control it as if you were right in front of it, but from anywhere.

Generally, you don't need to install anything extra to use it, especially if you are on Windows, since it was created by Microsoft and comes integrated into the operating system.

It is widely used for things like providing technical support, managing servers or collaborating on projects remotely, all in real time and without having to be physically in the same place as the machine.

How does RDP work?

To start using RDP, you need to have two things clear: a device from which you are going to connect (the client) and another one to which you are going to connect (the server).

On the computer you are going to use to connect, you must have client software installed (although in Windows it comes ready to use). And on the other computer (the one that is going to receive the connection) the RDP server software must be enabled, which is also usually enabled by default in many versions of Windows.

Once both are configured, the connection between them is established using port 3389, which is the one that RDP uses by default. Through this connection everything that happens in the remote session is sent: mouse clicks, what you type on the keyboard, window movements... basically everything you would do if you were in front of the other computer.

And so that no one gets in where they shouldn't, all this information is encrypted, which means that it is protected so that cybercriminals can't intercept or spy on it.

Advantages and disadvantages of RDP

Like any technology, RDP has its strengths and limitations:

Advantages

1. You don't need to use a VPN to connect, which simplifies things quite a bit.

2. You can use it from almost any computer, even one that is not very powerful.

3. You can access your remote computer whenever you want, without being physically there.

4. It is ideal when you need to work with data that, for legal or compliance issues, must be stored locally.

Disadvantages

1. You need to configure software on both computers, which can be a barrier if you are not familiar with this.

2. Sometimes, if the connection is not very good, there may be a slight delay in actions (such as moving the mouse or opening windows).

3. It works best on Windows, so if you use other operating systems it can be more complicated.

4. And yes, it has security vulnerabilities that have been exploited by attackers, that's why it is so important to configure it well and keep it protected.

Read more: What Is Ransomware? How to Prevent

Security vulnerabilities in RDP: What you need to know

Using RDP can be very useful, but if not configured properly, it can also become a great gateway for cyberattacks. Many ransomware cases have started precisely like this: someone leaves remote access poorly protected and attackers take advantage of it to get in and cause a disaster.

The problem is that RDP uses port 3389 by default, which, if it is open to the Internet without any protection, is like leaving your front door unlocked. There are automated tools that scan thousands of IP addresses looking for just that: misconfigured access.

And although RDP encrypts the data sent during the session, that doesn't mean it's 100% secure. If someone manages to get in, they can access everything as if they were using your computer directly.

Case studies: How misuse of RDP can cost millions

Several companies have suffered serious consequences for not properly securing their remote access. One of the most notorious cases was that of the Düsseldorf Hospital in Germany, where a ransomware attack initiated through RDP caused the collapse of critical systems and the death of a patient who had to be redirected to another medical center.

Another example is the case of the attack on Colonial Pipeline in the United States, where a ransomware group exploited compromised credentials to access the internal network, disrupting the fuel supply to millions of people.

How to secure an RDP connection?

Nowadays, with so many people connecting remotely, it is not enough to “install and use”. You have to take security seriously. Here are some recommendations that really make a difference:

1. No easy passwords: forget about using “123456” or “admin”. Use long, complex and different passwords for each user. And if you can, enable multi-factor authentication (MFA).

2. Enable a firewall: set up rules so that only certain IPs (for example, those of your office or authorized equipment) can try to connect.

3. Keep everything up to date: make sure you have the latest version of Windows and RDP. Updates fix vulnerabilities that could be exploited if left unpatched.

4. Restrict access: only give permission to people who really need it. No generic or uncontrolled accounts. And keep track of who logs in and when.

5. Use a VPN: instead of exposing RDP directly, ask for the connection to be made via VPN first. It's an extra layer that makes it much more difficult for someone to get in without permission.

6. Limit failed attempts: configure the system so that after several failed login attempts, the account is temporarily locked. This stops brute force attacks.

The use of the RDP protocol does not have to be dangerous. The real problem lies in the lack of proper configuration and protection. If the right measures are taken, it can be a useful and secure tool for remote administration and access. 

Remember: it's not about stopping using RDP, it's about using it wisely. And the sooner you start applying these recommendations, the better protected you will be.

At TecnetOne, we not only work on security solutions, but we also help your company's teams to stay updated and prepared against digital threats. Our approach combines technology, training and best practices to strengthen cybersecurity from within.