One Identity Safeguard for Privileged Sessions 6.2.0 - Administration Guide

One Identity Safeguard for Privileged Sessions (SPS) deployment scenarios in a Citrix environment

This section enlists the available One Identity Safeguard for Privileged Sessions (SPS) deployment scenarios in a Citrix environment. The text on the arrows are formatted in (<step number>) <target port> format. The target ports define the protocols used in the communication:

• 80: Web service, HTTP: the list of available resources fetched in an XML format from the broker (v12 and v11 with Citrix Virtual Apps (formerly known as Citrix XenApp) only). The broker sends all the necessary information, including secure gateway and server addresses to the client.

• 8080: XML service, HTTP+XML: application discovery, load balancing (v12 and v11 with Citrix Virtual Apps (formerly known as Citrix XenApp) only), used to fetch target to the application/desktop by the client from the broker (used for load balancing, and so on).

• 443: XML service access or SOCKS/ICA or CGP/ICA wrapped in TLS. The client communicates with the secure gateway on this port for everything.

• 1080: SOCKS. The client can be configured to access the target server and the broker using a SOCKS proxy.

• 1494: Plain ICA.

• 2598: CGP/ICA (reliable mode enabled).

Client - SPS - Server (Transparent mode)

The SPS is deployed between the client and the server and the clients use predefined connection files or Program Neighbourhood, without a broker or secure gateway. The clients try to connect to their original ICA/CGP server.

Figure 172: Client - SPS - Server (Transparent mode)

Client - SPS - Server (Non-transparent mode)

The SPS is deployed between the client and the server and the clients use predefined connection files or Program Neighbourhood, without a broker or secure gateway. The clients try to connect to SPS, which can distinguish between the potential targets for example by source IP, or by having multiple IP addresses itself.

Figure 173: Client - SPS - Server (Non-transparent mode)

Client - Broker - SPS - Server (Transparent mode)

The clients are using a farm broker which gives them a list of the available applications and servers, but they do not use a secure gateway in the network. The SPS is placed between the clients and the servers in transparent mode, and it catches the connections when the clients try to connect to the server IP addresses they got from the broker.

Figure 174: Client - Broker - SPS - Server (Transparent mode)

Client - Broker - original secure gateway - Secure Ticket Authority (STA) - SPS - Server

In this setup, a secure gateway is used in the network and the SPS is placed between this gateway and the servers in transparent mode. The clients connect to the broker for the list of available applications/servers and then make their further connections through the original secure gateway. That gateway forwards the connections either to the broker or to the CGP/ICA servers, which latter the SPS intercepts and audits/controls.

Figure 175: Client - Broker - original secure gateway - Secure Ticket Authority (STA) - SPS - Server

Client - Broker - SPS as socks proxy - Server

In this setup, the SPS acts as a SOCKS proxy for the client. It can be set either manually or specified by the broker. The client then makes all its connections to the broker or to the server using SPS as a proxy and hence it can audit/control these connections.

Figure 176: Client - Broker - SPS as socks proxy - Server

To configure such a scenario, you must set the ICA Connection Policy as follows:

• Enter the IP address of SPS into the To field. This must be the public IP address that the clients will target.

• Select Inband destination selection, and list the IP addresses or networks of target servers in the Targets field. (For details, see Configuring inband destination selection.)

• Select Act as a SOCKS proxy.

• Add the IP addresses of your brokers to the Brokers field.

Troubleshooting Citrix-related problems

Accessing Citrix servers using the Remote Desktop Protocol

Accessing Citrix servers using the Remote Desktop Protocol may fail in certain situations, and the connection is terminated with the ERROR: error while decompressing packet error message on the client, or with the Event56, TermDD, The Terminal Server security layer detected an error in the protocol stream and has disconnected the client. message on the server.

To overcome this problem, modify the settings of the network card of the server, and disable the Large Send Offload option.

RDP-specific settings

The following sections describe configuration settings available only for the RDP protocol. Use the following policies to control who, when, and how can access the RDP connection.

• Channel Policy: The channel policy determines which RDP channels (for example clipboard, file-sharing, and so on) can be used in the connection, and whether they are audited or not. The different channels may be available only under certain restrictions, as set in the channel policy. For details, see Creating and editing channel policies.

• RDP settings: RDP settings determine the parameters of the connection on the protocol level, including timeout value, display parameters, and the version of RDP permitted. For details, see Creating and editing protocol-level RDP settings.

• Domain membership: When using Network Level Authentication (CredSSP) One Identity Safeguard for Privileged Sessions (SPS) must be a member of the domain. For details, see Network Level Authentication (NLA) with domain membership.

• TLS-encrypted connections: For details on how to setup TLS-encrypted RDP connections, see Enabling TLS-encryption for RDP connections and Verifying the certificate of the RDP server in encrypted connections.

• SPS as a Remote Desktop Gateway: For details on how to configure SPS to accept connections using the Remote Desktop Gateway Server Protocol, see Using One Identity Safeguard for Privileged Sessions (SPS) as a Remote Desktop Gateway.

• Content Policy: Content policies allow you to inspect the content of the connections for various text patterns, and perform an action if the pattern is found. For example, SPS can send an e-mail alert if a specific window title appears in RDP and VNC connections. For details, see Creating a new content policy.

• Authentication and Authorization plugin:

  One Identity Safeguard for Privileged Sessions (SPS) provides a plugin framework to integrate SPS to external systems to authenticate or authorize the user before authenticating on the target server. Such plugins can also be used to request additional information from the users, for example, to perform multi-factor authentication.

  For details, see Integrating external authentication and authorization systems.

Using multiple monitors (Multimon) is supported. To enable Multimon, use one of the following three methods:

• enable Display > Use all my monitors for the remote session option in the Remote Desktop Client (mstsc.exe) window of the client machine

• use the /multimon switch on the mstsc.exe command line

• add the use multimon:i:1 row to the RDP file

Limitations

The RDP connection fails due to the following Windows-side settings:

• If the target user is a member of the Protected Users security group.
• If Remote Credential Guard is enabled and used.
• If Restricted Admin mode is enabled and used. For more information on how to enable or disable the Restricted Admin mode on Windows, see Remote Desktop Services: Enable Restricted Admin mode.

Supported RDP channel types

The available RDP channel types and their functionalities are described below. For details on configuring Channel Policies, see Creating and editing channel policies. For a list of supported client applications, see Supported protocols and client applications.

• Drawing: Enables access to the server's graphical desktop (screen). This channel must be enabled for RDP to work.

  NOTE:

  In case the Drawing channel is disabled and the load of One Identity Safeguard for Privileged Sessions (SPS) is high, or the connection requires four-eyes authorization and the Authorizer is slow to accept the connection, the client might receive the following error message:

  The Remote Desktop Gateway server administrator has ended the connection.
  Try reconnecting later or contact your network administrator for assistance

• Clipboard: Enables access to the server's clipboard: the clipboard of the remote desktop can be pasted into local applications (and vice-versa). Note that SPS can audit the clipboard channel, and that files transferred via the clipboard can be audited Configuring SPS to enable exporting files from audit trails after RDP file transfer via clipboard.

  If the Clipboard channel is enabled, it implicitly enables copying files as well, as the user can simply copy-paste the file. Copy-pasted files will not be visible in the logs or the File operations column of the Search page. To ensure that SPS records file transfer events, you must disable the Clipboard channel.

• Redirects: Enables access to every device redirection available in RDP, like file-sharing, printer sharing, device (for example, CD-ROM) sharing, and so on.

  • To make the list of file operations available in the File operations column of the Search page, navigate to the Channel Policies page of the protocol, and enable the Log file transfers to database option. This option is disabled by default.

  • To send the file operations into the system log, enable the Log file transfers to syslog option. This option is disabled by default.

    NOTE:

    Turning logging on might result in a slight performance penalty. If traffic load slows processes down, disable the option.

  To enable only specific types of redirections, use the following channels:

  • Serial redirect: Enables access to serial-port redirections.

  • Parallel redirect: Enables access to parallel-port redirections.

  • Printer redirect: Enables access to shared printers.

    When enabling printer redirection, you may need to use TSVCTKT and XPSRD channels — these enable XPS printing.

    Note that these channels are dynamic virtual channels and you have to be enable them using the Custom channel type.

    For more information on TSVCTKT and XPSRD channels, see section 2.1 Transport in Microsoft Technical Document [MS-RDPEXPS].

    Before consulting the cited Microsoft Technical Document, it is recommended to start by reading [MS-RDSOD]: Remote Desktop Services Protocols Overview.

  • Disk redirect: Enables access to shared disk drives.

    • To make the list of file operations available in the File operations column of the Search page, navigate to the Channel Policies page of the protocol, and enable the Log file transfers to database option. This option is disabled by default.

    • To send the file operations into the system log, enable the Log file transfers to syslog option. This option is disabled by default.

      NOTE:

      Turning logging on might result in a slight performance penalty. If traffic load slows processes down, disable the option.

    If the Clipboard channel is enabled, it implicitly enables copying files as well, as the user can simply copy-paste the file. Copy-pasted files will not be visible in the logs or the File operations column of the Search page. To ensure that SPS records file transfer events, you must disable the Clipboard channel.

  • SCard redirect: Enables access to shared SCard devices.

  To permit only specific redirections, enter the unique name of the redirection into the Details field. For example, if you want to enable access only to the shared disk drive C:, enable the Disk redirect channel and enter C: into the Permitted devices field. Note that the name of the device comes from the device itself, so it is case sensitive, and may not always be reliable from a security point of view.

• Sound: Enables access to the sound device of the server.

• Custom: Applications can open custom channels to the clients connecting remotely to the server. Enabling the Custom channel allows the clients to access all of these custom channels. To permit only specific channels, enter the unique names of the channel into the Permitted devices field.

  For example, to monitor RemoteApp connections, you need to configure custom channels. For more information, see Configuring RemoteApps.

• Seamless: Enables seamless channels that run a single application on the RDP server, instead of accessing the entire desktop.

• Dynamic virtual channel: Enables the server to open channels back to the client dynamically. To restrict which dynamic channels are permitted, select Channel details, click and enter the name of the permitted channel.

  Additionally, you may need to use one or more of the following:

  • PNPDR and FileRedirectorChannel channels: Enable Plug and Play devices.

    For more information, see section 2.1 Transport in Microsoft Technical Document [MS-RDPEPNP].

  • URBDRC channels: Enable USB redirection.

    For more information, see section 2.1 Transport in Microsoft Technical Document [MS-RDPEUSB].

  Before consulting any of the listed Microsoft Technical Documents, it is recommended to start by reading [MS-RDSOD]: Remote Desktop Services Protocols Overview.