Microsoft Remote Desktop Services Security Best Practices
Microsoft Remote Desktop Services Security Best Practices. Remote Desktop Services (RDS) by Microsoft allows users to remotely connect to and control computers over a network. RDS improves flexibility and collaboration, but also introduces potential security risks. It enables multiple users to simultaneously connect to a single Windows server machine, each with their own independent desktop session experience.
This article provides some best practices to secure your RDS environment and protect it from cyber attacks. Read on!
Let’s dive deep into Microsoft Remote Desktop Services Security Best Practices.
Microsoft Remote Desktop Services Security Best Practices
1. Use Multi Factor Authentication (MFA)
Multi factor authentication is more than one method of authentication: username/password and another such as one time password. Implementing MFA helps secure your RDS for additional layer security if primary credentials get compromised. With MFA, you secure your RDS against social engineering, phishing, and brute force attacks.
To implement MFA, consider using Microsoft Authenticator or third-party MFA providers. They integrate seamlessly with Windows environments and enforce MFA for all remote desktop connections.
2. Use an RDP Gateway Server
An RDP Gateway Server is a central access point for remote connections. It improves security by encapsulating RDP traffic within an HTTPS tunnel providing a higher level of encryption. With an RDP Gateway, you channel all connections through a single entry point. It is easier to monitor and control access, enforce security policies, and detect suspicious activities. This prevents attackers from eavesdropping on RDP traffic traveling over public networks.
The RDP Gateway Server is like a secure bridge between external users and the internal network to keep RDS secure. This setup prevents direct exposure of internal networks to the internet, reducing the attack surface on the remote desktop services. Besides, it provides a controlled environment for remote access. Use this controlled environment to extend access to remote users without compromising on security. It simplifies the management of remote connections, allowing IT teams to implement consistent security policies.
3. Implement the Principle of Least Privilege
The Principle of Least Privilege requires that you only provide users with the necessary permissions they need to perform their tasks. In an RDS, this principle can help minimize the risk of malicious activity. It ensures attackers have minimal opportunities to access sensitive information to launch a breach. Enforcing this principle on your RDS environment significantly limits the potential damage caused by compromised accounts.
For this principle to work, review user accounts and group memberships on your RDP servers regularly. This way, you identify and review all permissions, and make changes to achieve the principle of least privilege. Remove any unnecessary admin privileges and ensure that users only have the level of access they genuinely need.
After making these changes, regularly review access controls and adjust them based on user job functions. Additionally, implement role based access control systems that streamline the management of access rights. This makes it easier to enforce the principle of least privilege across the organization.
4. Change the Default Port
By default, RDP uses TCP port 3389 for connections. However, hackers are aware of it, this makes it a potential target. Therefore, change the default port to a less predictable one to reduce attack surface. It makes it harder for attackers to identify RDP services on the network. Besides, attackers are less likely to target non-standard ports, reducing the overall number of attacks on your system.
Once you change the port number, also update firewall rules to allow traffic through the new port.
5. Implement Network Level Authentication (NLA)
Network Level Authentication (NLA) is an authentication mechanism that requires users to authenticate themselves before establishing a full RDP session. This helps protect against denial-of-service (DoS) attacks and brute-force login attempts.
To implement NLA configure both the RDP server and client to support and require NLA for connections. This configuration is much more direct in Windows systems as they support NLA out of the box. It’s crucial to ensure RDS users have systems that support NLA, as some might not be able to connect without additional configuration.
6. Tunnel Remote Desktop Connections Through IPSec or SSH
IPSec provides a robust suite of protocols designed to secure IP communications by authenticating and encrypting each IP packet in a data stream. SSH, on the other hand, provides a secure channel over an unsecured network in a client-server architecture. Ideally, it creates an encrypted tunnel that protects data in transit. This is ideal for temporary and less frequent RDP connections.
7. Implement Network Segmentation
Network segmentation creates smaller yet more manageable subnets of your network. Each network subnet has its own security controls and policies to minimize lateral movement within the network. This helps improve the overall security of the RDS, as it makes it easier to counter a security breach.
In the event that an attacker compromises a particular subnet, the breach is easily contained within that subnet. Particularly useful in large organizations where there are large networks and different departments working separately.
Mostly, organizations use VLANs to create multiple network segments. Further, they use Access Control Lists(ACLs) and firewalls to enforce security rules. The resources accessed via RDS can have isolated segments and strict access controls to enhance security. With proper network segmentation, you also achieve performance improvements, as you easily identify and isolate issues.
8. Secure Remote Administrator Access
Is critical in protecting systems and sensitive data that administrators manage. This involves implementing stringent authentication methods and ensuring that all remote access sessions are conducted through secure, encrypted channels.
Also, you should highly restrict remote admin access to production environments. This means you have to use dedicated administrator accounts that are separate from regular user accounts. Admins should use secure, dedicated workstations for remote access. This minimizes the risk of exposing administrative credentials through less secure environments. Finally, remember to regularly review and revoke unnecessary privileges for users with admin accounts.
9. Enable Automatic Microsoft Updates
Since RDS runs on windows systems, enable automatic Microsoft updates. This ensures that both the operating system and RDS servers receive the latest security patches and improvements.
Use Windows Server Update Services (WSUS) or a third-party patch management solution to manage the patch deployment process. This allows you to test patches before deploying them to production and gives you granular control over the process.
10. Implement a SIEM Solution
A Security Information and Event Management (SIEM) solution enables you to monitor and analyze all security events across a network. SIEM tools aggregate log data from various sources, including RDS to provide a centralized view of the security posture.
11. Limit Login Attempts
On many occasions, attackers launch brute force attacks by guessing multiple combinations of usernames and passwords. Configure account lockout policies on your RDP servers to lock accounts after a certain number of failed attempts. For instance, set the minimum logon attempts to 10.
12. Implement Patch Management
Patch management is multi process, and involves identifying, testing, and applying patches to mitigate vulnerabilities. When working with RDS, patch management goes beyond just Microsoft Updates.
It simplifies the process of tracking vulnerabilities and deploying patches across your environment. Also, you should regularly test patches in a staging environment before deploying them into production.
13. Implement Network Firewalls
Firewalls are essential for any networked environment, but especially critical for securing RDS. Network firewalls act as a barrier between the internal network and untrusted external networks, such as the internet. They filter incoming and outgoing network traffic based on predetermined security rules. They block unauthorized access while permitting legitimate communications. It’s therefore recommended to deploy a network-level firewall to create an additional layer of defence, filtering traffic entering and leaving your network.
Always configure your firewall with strict rules, allowing inbound traffic only from specific, trusted IP addresses or subnets. Also, it’s best to use a stateful firewall for extra protection. Stateful firewalls track the state of active connections, ensuring that traffic is part of legitimate sessions. This helps mitigate unauthorized connection attempts and network scanning activity.
Use host based firewalls on your RDP servers to add a second defensive layer. They block non-essential ports and protocols. This significantly minimizes the attack surface, making it harder for malware to spread if a breach does occur within your network.
14. Restrict Device Redirection
Device redirection in RDS allows users to access local resources, such as drives, printers, and USB devices, during a remote desktop session. However, while it provides some convenience, it also poses a significant security risk. A compromised device on the user’s end could serve as a pathway for malware to enter your network. Therefore, before allowing device redirection, you should assess whether your users require this functionality. If not, disable device redirection entirely within your RDS configuration.
In the event that you need device redirection, implement it cautiously. First, use RDS policies to permit only the precise devices essential for user operations such as specific printers or approved USB storage devices. Besides that, log and audit device redirection activity continuously. This helps detect any anomaly that could indicate attempts to introduce malware through compromised devices.
15. Implement Encryption
Always enforce the highest encryption level that your clients and your RDS environment support. This ensures the strongest protection for data flowing across remote sessions, making interception far more difficult.
For additional security, consider tunneling RDP through IPSec or SSH. IPSec encrypts traffic at the network layer, providing robust protection for all data transmitted to and from your RDP servers. SSH creates a secure “tunnel” for RDP data, often used for quick or temporary secure connections.
Regularly review encryption standards and update your RDS configuration as newer, stronger encryption protocols become available. Encryption is a key defense against “man-in-the-middle” attacks and sensitive data leakage.
16. Implement Proper Session Management
Idle RDP sessions pose a risk and can easily allow unauthorized access. You should configure timeouts that automatically disconnect sessions after a defined period of inactivity. This prevents unauthorized users from accessing open sessions.
Also, set limits on session duration to force users to periodically re-authenticate. This ensures users have to re-authenticate after a certain time, even if they’re active. Finally, ensure you log all RDP session activity, including connection times, durations, and termination reasons. You can rely on this data to investigate security incidents and identify potential patterns of unauthorized access.
Thank you for reading Microsoft Remote Desktop Services Security Best Practices. Concluding below.
Microsoft Remote Desktop Services Security Best Practices Conclusion
Rely on the above security practices to secure your RDS implementation. You are more capable of protecting your organization against cyber threats.
