What is an RDP Brute Force Attack?

Remote desktop protocol (RDP) is a secure proprietary communication protocol initially built by Microsoft. It allows two PCs to share a graphical user interface (GUI) over a standardized transmission control protocol (TCP)/internet protocol (IP) connection. It gives users remote access to their corporate resources. IT teams can also leverage RDP to remotely diagnose issues that individual users encounter in an organization. Here’s an article that explains in detail what RDP meaning is. Even though RDP has inbuilt data encryption capabilities, activity logging, and access controls, the protocol introduces additional security vulnerabilities that adversaries can use as attack points. An RDP brute force attack is one method adversaries can use to infiltrate a network.

It occurs when an adversary attempt every possible method—usually with an automated solution—to gain access to a network in an RDP session. For example, an attacker could use tools that repeatedly auto-attempt a user’s credentials until they have successfully penetrated the computer. Once inside the victim’s computer, an attacker can then proceed to access the entire enterprise’s network.

The Vulnerabilities of RDP

RDP is an efficient way to create a virtual desktop infrastructure (VDI) and remotely offer network access to multiple users. RDP servers enable businesses to leverage resources and improve business productivity levels, as resources are always available to employees. The growing popularity of bring-your-own-device (BYOD), virtualization, and cloud computing environments have resulted in millions of remote networks across the globe.

Remote network tools come preinstalled in Windows OS, offering a handy platform for businesses. While RDP networks are popular with businesses of all sizes, hackers love them too. The recent RDP exploits watch from Security researcher Dan Kaminsky reveals that there are almost 5 million RDP endpoints that provide online access. Hackers are trying to enter into business networks by exploiting remote network vulnerabilities. Essentially, an unsecured RDP network offers an ideal scenario for a brute force attack.

The MS12-020 in the Microsoft RDP tool is an example of RDP vulnerability, and Microsoft has already released a patch for this issue. At the same time, it is estimated that each computer on a network experience at least 50 probes per day, according to an article published by Sophos Naked Security. These statistics show how important it is to secure your RDP networks.

Why should Businesses Secure their RDP Network?

While the RDP tool offers greater benefits for organizations, leaving your remote networks open can create a huge disaster. Hackers scan the network for open RDP ports. Normally, port 3389 is used for RDP connections. By applying brute force, hackers can get a remote connection. Once a remote connection is established, hackers can spread a virus or use the server for further hacking purposes.

With an open RDP endpoint, organizations face greater risks. Especially for businesses that deal with critical data, securing your remote networks is very important. For instance, hackers can use a remote banking application and illicitly transfer money from users’ accounts. Whether it is for fun or for profit, RDP vulnerabilities can cost you a great deal.

There are certain business networks that do not use mission-critical data. Moreover, they do not perform important business processes. Even then, it is still important to secure RDP connections as hackers can use these remote desktop servers for network attacks. It is interesting to point out that most of the RDP probes come from hacked systems. While you may believe that there is nothing that hackers can gain from accessing your remote networks, you should be aware that your servers can become part of the hacking, too.

How can Businesses Secure RDP Networks?

The best way to prevent hackers from accessing your RDP open end points is to create a VPN tunnel that can effectively filter incoming RDP connections. The filtering of remote incoming connection can be based on IP, MAC, client version or the computer name.

By securing your open RDP end points using a VPN tunnel, businesses can effectively enhance the security of windows terminal services. In addition, businesses can practice security measures like using strong passwords, updating security tools on a regular basis, enabling network level authentication, and setting up account locking policies. .

Methods of RDP Brute Force Attack

An adversary can use any one of the following RDP brute force attack methods to gain access to a network:

Reverse brute force attack. In this attack, an adversary employs a single password or multiple passwords against a large set of potential usernames. For example, suppose an attacker knows the identity credentials of a given user or at least a piece of it, such as the date of birth. Such an attacker can use the learned information to attempt a predefined set of usernames and random passwords to gain access to a network.
Hybrid brute force attack. This attack begins when an attacker uses the most likely combinations of users’ credentials and repeatedly tries several attempts to gain access to a network. You can think of a hybrid brute force attack as a dictionary attack where the hacker attempts to guess credentials against a dictionary of potential phrases and letters.
Credential stuffing. This is a kind of attack where the adversary has a database containing login credentials (often acquired from data breaches) and uses such data to try accessing several systems. Credential stuffing can be detrimental in cases where a user has reused passwords on multiple systems.
Rainbow table attack. This is a password cracking approach that leverages a special table—also called “rainbow table”—to guess password hashes in a database. Any attacker that gains access to a list of password hashes can use this approach to crack all passwords and infiltrate a network.

Secure Yourself from an RDP Brute Force Attack with Parallels RAS

It’s no secret that the shift to hybrid working environments is having lasting effects on the modern workforce landscape. To succeed in such working environments, it’s crucial to ensure that remote access solutions that employees leverage to access corporate resources are secure and fit into the organization’s budget.

Parallels RAS (Remote Application Server) is a low-cost, easy-to-use, and secure virtual desktop infrastructure (VDI) solution employees can leverage to access virtual workloads from any endpoint. With Parallels RAS, IT teams can easily prevent some attacks associated with RDP sessions via a gateway protection setting.

Besides preventing RDP attacks, Parallels RAS reinforces security via additional protection layers, such as multi-factor authentication (MFA), kiosk mode, advanced filtering, and clipboard restriction.

The platform also extends remote desktop services (RDS) capabilities, allowing users to access full-featured virtual workloads from heterogeneous devices. Some of the capabilities that Parallels RAS support include drag and drop, zoom, and multi-screen. Most importantly, Parallels RAS supports various RDP clients that employees can use to access published applications and desktops, including Windows (Parallels RDP for Windows), macOS (Parallels RDP for Mac), and Linux.

Try out Parallels RAS today and discover its potential in preventing RDP brute force attacks!

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