RDP security: How to secure your remote desktop

With 27% of the US workforce operating remotely, companies need efficient and secure ways to connect users and central servers.

Microsoft's Remote Desktop Protocol has become a go-to option for flexible working. More than 50% of companies report using RDP in the past year, and it's not hard to see why. RDP allows fast connections and seamless remote work.

But is RDP a secure option for your workforce? As always, the answer depends on your security setup.

This blog will explore how RDP works and some of the main RDP vulnerabilities. As we will see, remote access creates significant security risks. However, these risks can be managed if you follow our RDP security tips and implement smart remote access solutions. Let's find out more.

What is RDP?

Businesses use the Remote Desktop Protocol (RDP) to communicate with and control external devices. Created by Microsoft, RDP enables seamless remote work via Windows systems.

RDP functions by creating sessions between clients and servers. Clients request access. Servers authenticate requests and transmit a graphical interface to the remote client. This interface replicates the desktop contained on the server and functions just as if installed on the client.

The Remote Desktop Protocol supports this setup by carrying data about mouse movements, clicks, and keyboard presses. The protocol converts activity into data packets, which the server converts into graphical updates.

In the process, a lot of information passes across the RDP connection. RDP access handles document printing, audio, and video communications, collaborative editing, and file transfers. Much of this information could be very valuable in the wrong hands.

Why use RDP?

RDP allows remote workers to access resources located in central data centers. Workers can run applications and manipulate files just as they would in on-premises offices. Users do not need to install apps locally or download documents for local use. Everything stays on-site.

RDP also enables technicians to access remote devices. On-site specialists can diagnose problems, deliver security patches, assess device postures, and monitor remote operations. Managers and security teams can easily train remote workers.

Technicians favor the RDP protocol due to its reliability and speed. Windows compatibility is another attractive feature, making it convenient for most organizations. However, there is a downside: RDP security issues.

What are the main RDP security issues?

RDP is a transfer protocol, and protocols are almost always vulnerable to external attacks. That's not all. Attackers can also target the servers and applications used to enable RDP access.

Attacks range from mild irritants to serious threats that put workloads and data at risk. Companies using RDP for remote work need plans to handle these threats and keep data safe.

Security planning starts with awareness of common RDP threats. Here are some of the most common (and damaging) vulnerabilities:

• Unsecured ports. RDP always uses port 3389 to establish connections. This is an external and open port. Malicious actors can impose themselves between users and port 3389 to steal credentials via on-path attacks. Attackers can then use the open port to access servers or devices.
• Credentials theft. Weak credentials are a critical RDP security issue. Users often reuse passwords for RDP and email and access web applications. Attackers obtaining these user credentials can implant ransomware via workloads or servers. Even slightly different passwords are vulnerable to brute-force attacks.
• Server exploits. In the past, Microsoft's RDP services have fallen victim to remote code execution vulnerabilities. Hackers use flaws in servers or protocol codes to gain unauthorized access. For instance, an exploit called BlueKeep once exposed millions of RDP servers to external attacks. Microsoft resolved the BlueKeep issue, but exploits can emerge at any time.
• Protocol tunneling. In tunneling attacks, hackers implant malicious code within protocol traffic. RDP traffic appears to be legitimate but carries malware or other harmful agents. Even worse, many standard firewalls struggle to detect this type of attack.
• Session hijacking. Attackers can gain access to active remote desktop access sessions. In these situations, attackers can explore any resources available to legitimate remote users. Until they are detected, they can implant malware, extract data, and disrupt operations.
• DDoS attacks. Attackers often use protocols to flood networks with traffic and take systems offline. RDP is vulnerable to DDoS-style attacks because it uses an open port, and servers generally do not enforce rate limits. The protocol is also relatively resource intensive, meaning attackers must unleash less traffic to achieve results.

How to secure RDP

Securing your Remote Desktop Protocol setup should be an urgent task. RDP is involved in 90% of cyberattacks, and the consequences of attacks are severe. RDP is a critical vector for ransomware, and attackers can use exposed work environments to steal confidential data.

There is some good news. Properly secured remote desktop protocol implementations are hard to infiltrate and secure. Let's run through some best practices to create a secure remote desktop environment.

• Use stronger passwords. Brute-forcing attacks are much harder to mount against complex passwords. Avoid any words related to individuals or the company, and always avoid recycling passwords from other logins. Use password managers to generate strong passwords that are impossible to guess.
• Change your RDP port. Changing your listening port from 3389 helps make RDP secure by limiting external access. Changing the port is a sensible first step, as it blocks many automated port attacks.
• Use access controls. Administrator accounts can change RDP settings or use their privileges to access other network resources. Use access management tools to apply the principle of least privilege. Provide access to administrators when they need it for specific tasks. Otherwise, allow the fewest possible permissions for all remote users.
• Apply firewall protection. Strengthen your defenses by casting Windows Firewall protection around RDP environments. Windows Firewall rules for RDP connections block external traffic but allow authorized users to access network resources.
• Use Network-Level Authentication (NLA). Network-level authentication is native to RDP systems and adds an extra layer of authentication for every session. Users seeking RDP access must supply an additional form of identification, such as smart cards, one-time passcodes, or biometrics.
• Implement lockout policies. Lockout policies block users after a certain number of unsuccessful logins. This is a good starting point for blocking brute-force attacks.
• Monitor user sessions. Track user activity during RDP sessions to detect suspicious behavior. Monitoring should check for spikes in resource usage. This could suggest a DDoS-style attack. Technicians should also monitor access to sensitive files and limit access to essential resources.
• Add Virtual Private Network (VPN) protection. VPNs ensure secure remote access by creating encrypted shields around remote connections. Users log onto a VPN gateway before accessing RDP servers. This adds an extra barrier for hackers and effectively anonymizes traffic.
• Update RDP tools regularly. Promptly apply security updates for remote desktop applications and Windows Server. Ensure VPNs, multi-factor authentication tools, and firewalls are up to date. Regular updates cut the risk of exploits, making life much harder for would-be attackers.
• Train staff in RDP security. Never allow remote workers to use RDP connections without security training. Ensure workers know how to use passwords, VPNs, and multi-factor authentication. Outline security and compliance policies.

Eliminate RDP vulnerabilities using NordLayer

RDP is among the most common secure remote access solutions available. Yet, it is not necessarily the best way to ensure secure remote access—at least not on its own.

The solution lies in combining Microsoft's security features with external security tools. On-board tools like NLA, port settings, and user monitoring all help. However, NordLayer's Smart Remote Access ensures secure RDP connections with end-to-end encryption. 

NordLayer provides secure remote access solutions to meet your remote device access needs. Create virtual LANs around every network endpoint and protect remote users via VPN coverage. Cloud LAN enables secure file sharing from device to device, troubleshooting others' devices, and using remote devices as virtual machines for work.

Benefit from the flexibility and efficiency remote work provides while avoiding security nightmares. To find out more, contact the NordLayer team today.