10.6. Procedure – Enabling TLS-encryption for RDP connections

Purpose: 

To enable TLS-encryption in an RDP connection policy, complete the following steps.

Prerequisites: 

Depending on your requirements, one or more of the following might be needed:

  • To use the same certificate for each session, an X.509 certificate and its private key are required. PSM can display this certificate to the peers on the client side. Use your own PKI system to generate these certificates, as they cannot be created on PSM. Note that the Common Name of the certificate must contain the domain name or the IP address of target machine. otherwise the clients might reject the certificate.

  • To generate certificates on-the-fly for a connection, a signing certificate authority is required. For details on creating a signing CA, see Procedure 7.12, Signing certificates on-the-fly.

Balabit recommends using 2048-bit RSA keys (or stronger).

Steps: 

  1. Navigate to RDP Control > Connections and select the connection policy in which you want to enable TLS.

    Figure 10.5. RDP Control > Connections — Enabling TLS-encryption for RDP connections

    RDP Control > Connections — Enabling TLS-encryption for RDP connections
  2. Set the encryption settings used between the client/server and PSM in the Transport security settings section.

    To require encryption, select TLS. When the connection is encrypted, PSM has to show a certificate to the peer.

  3. Select the certificate to show to the peers.

    • If you want to enable TLS-encryption, but you do not have a certificate that is generated by an external CA, or a signing CA, select Generate self-signed certificate. This option is selected by default.

    • To use the same certificate for every peer, complete the following steps.

      1. Generate and sign a certificate for PSM in your PKI system, and export the certificate and its private key.

      2. Select Use the same certificate for each connection.

      3. Select Private key for host certificate, click and upload the private key.

      4. Select X.509 host certificate, click and upload the certificate.

    • If you want to use your own Signing CA, complete the following steps.

      1. Create a certificate authority that will be used to sign the certificates that PSM shows to the peer. For details, see Procedure 7.12, Signing certificates on-the-fly.

      2. Select Generate certificate on-the-fly.

      3. In the Signing CA field, select the certificate authority to use.

    • To disable TLS encryption for RDP connections completely, select Legacy RDP Security Layer (also known as: Standard RDP Security). You might want to do this if you were using legacy RDP encryption, and you are experiencing compatibility issues. For example, you might experience compatibility issue when you attempt to connect to a very old Windows machine (for example, Windows Server 2003 or older).

      Warning

      Security Hazard!

      Selecting this option can significantly reduce the strength of the encryption used!

  4. Optional step: If you were using legacy RDP encryption, and you are experiencing compatibility issues, select Allow fallback to legacy RDP Security Layer (also known as: Standard RDP Security). For example, you might experience compatibility issue when you attempt to connect to a very old Windows machine (for example, Windows Server 2003 or older).

    Warning

    Security Hazard!

    Selecting this option can significantly reduce the strength of the encryption used!

  5. Click .

    Expected result: 

    The encryption settings are applied to the connection policy.