How to Protect RDP from Ransomwares

Why RDP is Vulnerable to Ransomware Attacks

RDP offers the convenience of remote connectivity, yet it often has security gaps. Misconfigured or unsecured RDP access points allow attackers easy entry into corporate networks. Understanding these vulnerabilities is the first step in securing RDP against ransomware.

RDP’s Role in Remote Access and Security Challenges

RDP enables IT teams to manage servers, troubleshoot issues, and provide remote support. However, these functionalities introduce risks if security best practices aren’t strictly followed. Many organisations, especially those with limited IT resources, may rely on default RDP settings, which often lack sufficient security measures. This oversight creates vulnerabilities, such as:

Default Port Exposure: RDP’s default port, 3389 is well-known and easily scannable by attackers.
Credential-Based Access: RDP typically relies on usernames and passwords, which can be targeted by brute-force attacks.
Insufficient Encryption: Some RDP configurations may lack encrypted connections, exposing session data to potential eavesdropping.

RDP vulnerabilities can lead to unauthorized access and expose sensitive resources. To secure RDP, organizations must address these core issues with layered security strategies, as detailed in the sections below.

Best Practices to Protect RDP from Ransomware Attacks

Securing RDP requires a combination of strategic policies, technical configurations, and vigilant monitoring. Implementing these best practices can significantly reduce the likelihood of ransomware attacks.

Restrict RDP Access with Firewalls and VPNs

RDP should never be directly accessible over the internet. Configuring firewalls and using VPNs can help control and monitor RDP access points.

Use a VPN to Secure Access

VPNs provide a private, encrypted channel that authorised users must connect through before accessing RDP, creating an added layer of authentication and reducing exposure to public networks.

VPN Configuration for RDP: Configure VPNs with strong encryption protocols, such as AES-256, to secure data in transit.
Network Segmentation: Place RDP servers on separate network segments accessible only through the VPN to contain potential breaches.

Configure Firewall Rules to Limit Access

Firewalls help control which IP addresses can access RDP, blocking unauthorized sources from attempting a connection.

Implement IP Whitelisting: Allow only pre-approved IP addresses or ranges, minimising the risk of unauthorised access.
Geo-blocking: Block IPs from countries where no legitimate access should originate, further reducing the attack surface.

In summary, VPNs and firewalls serve as essential barriers, controlling who can attempt to access RDP. These configurations significantly limit potential attack vectors and prevent unauthorized direct access.

Enable Multi-Factor Authentication (MFA)

Relying solely on usernames and passwords is insufficient for RDP. Multi-factor authentication (MFA) requires additional verification, effectively reducing risks associated with credential theft.

Benefits of Implementing MFA on RDP

MFA adds a secondary layer that hackers must bypass, making brute-force attacks ineffective even if credentials are compromised.

MFA Integration with RDP: Use MFA solutions compatible with RDP, such as Microsoft Authenticator, which can integrate natively for prompt, secure verification.
Hardware and Biometric Options: For advanced security, implement hardware tokens or biometrics for MFA, providing an additional layer of physical security.

Centralized Management of MFA Policies

Organizations with multiple RDP endpoints benefit from centralized MFA management, simplifying policy enforcement.

Active Directory (AD) Integration: If using Microsoft AD, implement MFA through centralised AD policies to ensure consistent protection across the network.
Conditional Access Policies: Use conditional access policies that enforce MFA based on factors like IP address and session risk level for enhanced control.

Implementing MFA ensures that stolen credentials alone cannot grant unauthorized access, adding a robust line of defence against unauthorized RDP sessions.

Enforce Strong Password Policies

Passwords remain a fundamental layer of security. Weak passwords make RDP susceptible to brute-force attacks, so enforcing stringent password policies is critical.

Creating and Enforcing Complex Password Requirements

Secure passwords are lengthy, complex, and periodically updated to minimise the risk of compromise.

Password Complexity Rules: Require passwords with a minimum of 12 characters, combining upper- and lowercase letters, numbers, and symbols.
Automated Password Expiration: Implement expiration policies requiring users to change their passwords every 60-90 days.

Account Lockout Policies to Counter Brute-Force Attacks

Account lockout policies help prevent repeated unauthorized login attempts by locking the account after several failed attempts.

Configurable Lockout Thresholds: Set lockout to trigger after a limited number of incorrect attempts, such as five, to minimise brute-force risks.
Progressive Delay Tactics: Consider policies that impose increasing time delays on successive failed attempts, further thwarting brute-force efforts.

Through robust password policies and lockouts, organizations can improve baseline RDP security, making unauthorized access harder for attackers.

Utilise an RDP Gateway for Secure Access

An RDP Gateway is a specialised server that routes RDP traffic, ensuring that RDP sessions are encrypted and reducing the exposure of individual machines.

How RDP Gateways Strengthen Security

RDP Gateways use SSL/TLS encryption, allowing secure tunnelling between the client and the server, mitigating risks of data interception.

SSL TLS Encryption: Use SSL/TLS encryption protocols to ensure RDP sessions are protected, minimising the risk of data theft.
Single Point of Entry: With an RDP Gateway, you centralise access control, allowing easier management and security monitoring.

Implementing Role-Based Access through the RDP Gateway

RDP Gateways also allow role-based access, enabling administrators to enforce precise access policies and control who can access RDP resources.

Group Policy Settings: Configure Group Policy to specify which users or groups can connect via the RDP Gateway, ensuring only authorised personnel gain access.
Monitoring and Auditing Logs: Centralise RDP session logging to the gateway for easier monitoring of unauthorised access attempts or abnormal activity.

Using an RDP Gateway provides a secure entry point and offers IT administrators centralised control, ensuring enhanced security and manageability.

Change the Default RDP Port

Attackers commonly scan for the default RDP port (3389) Changing this port can make RDP access harder to identify, reducing exposure to automated attacks.

Configuring Custom Ports

Changing the RDP port provides a minor but beneficial security improvement, making it less likely that automated scripts will detect the RDP endpoint.

Select a Non-Standard Port: Choose a high, randomised port number (e.g., between 49152 and 65535) to reduce visibility.
Document Port Assignments: Maintain documentation of custom port configurations to avoid operational disruptions.

Limitations of Port Changing as a Security Measure

While changing the port can add slight obfuscation, it should never replace fundamental security measures like firewalls and MFA.

Switching the RDP port adds a modest layer of obscurity, but it is most effective when combined with other security measures as a defence-in-depth strategy.

Configure Account Lockouts and Monitor Login Attempts

Account lockouts are essential for protecting RDP against persistent login attempts, while monitoring adds an additional layer of vigilance.

Setting Up Account Lockouts to Thwart Attackers

Account lockouts prevent an account from being used after several incorrect login attempts, making brute-force attacks impractical.

Lockout Duration: Set temporary lockout periods (e.g., 30 minutes) to dissuade attackers.
Notify IT Administrators: Trigger alerts for IT teams if lockout thresholds are reached frequently, indicating potential brute-force attempts.

Establishing Real-Time Monitoring and Alerts

Monitoring abnormal RDP session activity can help IT teams detect and respond to potential threats swiftly.

Implement SIEM Tools: Security Information and Event Management (SIEM) tools provide real-time alerts and log analysis for unauthorised access.
Regular Log Reviews: Establish a routine for reviewing RDP access logs to identify suspicious patterns that could indicate compromised accounts.

Combining account lockouts with monitoring ensures that brute-force attempts are thwarted, and suspicious behaviour is quickly addressed.

Limit Access with the Principle of Least Privilege

Restricting RDP access to only essential users minimises the risk of unauthorised access and limits potential damage if an account is compromised.

Implement Role-Based Access Controls (RBAC)

Granting RDP access based on roles ensures that only authorised individuals have access, reducing unnecessary exposure.

Role-Specific Access Policies: Configure user groups based on role requirements and assign RDP privileges accordingly.
Restrict Administrative Access: Limit RDP access to administrators, applying stringent policies for privileged users.

Using Active Directory for Centralized Access Management

Active Directory (AD) offers centralized control over user privileges, enabling IT teams to enforce least-privilege principles across RDP connections.

Applying least privilege principles reduces the risk profile by ensuring only necessary users access RDP, limiting potential attack points.

Regularly Update RDP Software and Systems

Keeping RDP software and operating systems up to date ensures that known vulnerabilities are patched, minimising exploitability.

Automate update processes where possible

Automating updates guarantee that systems remain protected without manual intervention, reducing the risk of oversight.

Patch Management Tools: Use tools to deploy updates on a regular basis and monitor for missed patches.
Critical Updates First: Prioritise updates addressing vulnerabilities specifically targeting RDP or ransomware.

Keeping software updated ensures RDP remains resilient against exploits targeting unpatched vulnerabilities.

Monitor RDP Sessions and Network Activity

Vigilant monitoring of RDP sessions and overall network traffic helps identify potential threats in real time.

Using Intrusion Detection Systems (IDS) for Network Monitoring

An IDS can identify abnormal traffic patterns associated with RDP exploitation attempts.

Deploy IDS on RDP Traffic: Configure the IDS to flag suspicious login attempts and unusual access times.
Correlate RDP logs with network activity: Cross-reference RDP access logs with network activity to detect unauthorised patterns.

Monitoring enables proactive threat detection, allowing rapid response to potential ransomware infiltration.

Protecting RDP with TSplus

TSplus Advanced Security offers powerful tools to protect your RDP environment. With features like two-factor authentication, IP management, and session management, TSplus enhances your RDP security, helping safeguard your organisation against ransomware threats. Explore TSplus to fortify your RDP connections and protect your business from cyber risks.

Conclusion

Securing Remote Desktop Protocol (RDP) against ransomware is essential for protecting organisational data and maintaining operational continuity. By implementing a comprehensive security strategy—covering restricted access, multi-factor authentication, account lockouts, and continuous monitoring—IT professionals can greatly reduce the risk of unauthorised access and ransomware infiltration.

Regular updates, adherence to the principle of least privilege, and proactive network monitoring complete a well-rounded approach to RDP security.