Secure Deployment Guide for Citrix Cloud Government

The Secure Deployment Guide for Citrix Cloud Government provides an overview of security best practices when using Citrix Cloud Government and describes the information Citrix collects and manages.

The Citrix DaaS Technical Security Overview provides similar information for Citrix DaaS (formerly Citrix Virtual Apps and Desktops service).

Note:

In this article, the term customer refers to government agencies and customers in the United States who use Citrix Cloud Government.

Control Plane

Guidance for administrators

• Use strong passwords and regularly change your passwords.
• All administrators within a customer account can add and remove other administrators. Ensure that only trusted administrators have access to Citrix Cloud Government.
• Administrators of a customer have, by default, full access to all services. Some services provide a capability to restrict the access of an administrator. Consult the per-service documentation for more information.
• Two-factor authentication for administrators is achieved using Citrix Cloud Government’s integration with Azure Active Directory.

Password compliance

Citrix Cloud Government prompts administrators to change their passwords if their current password is more than 60 days old. New passwords must meet all the following criteria:

• At least 12 characters long
• Include at least one upper-case and lower-case letter
• Include at least one number
• Include at least one special character: ! @ # $ % ^ *? + = -

Rules for changing passwords:

• At least one character in the current password must be changed. The current password can’t be used as a new password.
• The previous 24 passwords can’t be reused.
• The new password must be in effect for at least one day before Citrix Cloud Government allows it to be changed again.

Encryption and key management

The control plane does not store sensitive customer information. Instead, Citrix Cloud Government retrieves information such as administrator passwords on-demand (by asking the administrator explicitly). There is no data-at-rest that is sensitive or encrypted. Therefore, you do not need to manage any keys.

For data-in-flight, Citrix uses industry standard TLS 1.2 with the strongest cipher suites. Customers cannot control the TLS certificate in use, as Citrix Cloud Government is hosted on the Citrix-owned cloud.us domain. To access Citrix Cloud Government, customers must use a browser capable of TLS 1.2 with strong cipher suites.

For more information about encryption and key management within each cloud service, consult the service’s documentation.

For more information about TLS 1.2 configuration, consult the following articles:

• CTX245765 Error: “The underlying connection was closed: An unexpected error occurred on a send.” when querying the Monitoring Service’s OData endpoint
• Update and configure the .NET Framework to support TLS 1.2 on the Microsoft Docs website.

Data sovereignty

The Citrix Cloud Government control plane is hosted in the United States. Customers can’t change the host location.

The customer owns and manages the resource locations that they use with Citrix Cloud Government. A resource location can be created in any data center, cloud, location, or geographic area the customer desires. All critical business data, such as documents, spreadsheets are stored in resource locations and are under customer control.

Audit and change control

There is no customer-visible auditing or change control available in the Citrix Cloud Government user interface or APIs.

Citrix has extensive internal auditing information. If a customer has a concern, they are advised to contact Citrix within 30 days. Citrix reviews the audit logs to determine the administrator who performed an operation. Reviews also the date on which it was performed, the IP address associated with the action.

Citrix Cloud Connector

Installation

For security and performance reasons, Citrix recommends that customers do not install the Cloud Connector software on a domain controller.

Also, the machines on which the Cloud Connector software is installed must be inside the customer’s private network and not in the DMZ. For network and system requirements and instructions for installing the Cloud Connector, see Create a resource location.

Configuration

The customer is responsible for keeping the machines on which the Cloud Connector is installed up-to-date with Windows security updates.

Customers can use antivirus alongside the Cloud Connector. Citrix tests with McAfee VirusScan Enterprise + AntiSpyware Enterprise 8.8. Citrix supports customers who use other industry-standard AV products.

In the customer’s Active Directory (AD), the Cloud Connector’s machine account must be restricted to read-only access. In Active Directory it’s the default configuration. Also, the customer can enable AD logging and auditing on the Cloud Connector’s machine account to monitor any AD access activity.

Logging on to the machine hosting the Cloud Connector

The Cloud Connector contains sensitive security information such as administrative passwords. Only the most privileged administrators are able to log on to the machines hosting the Cloud Connector (for example, to perform maintenance operations). In general, there is no need for an administrator to log on to these machines to manage any Citrix product. The Cloud Connector is self-managing in that respect.

Do not allow end users to log on to machines hosting the Cloud Connector.

Installing more software on Cloud Connector machines

Customers can install antivirus software and hypervisor tools (if installed on a virtual machine) on the machines where the Cloud Connector is installed. However, Citrix recommends that customers do not install any other software on these machines. Other software creates more possible security attack vectors and might reduce the security of the overall Citrix Cloud Government solution.

Inbound and outbound ports configuration

The Cloud Connector requires outbound port 443 to be open with access to the internet. The Cloud Connector with no inbound ports accessible from the Internet.

Customers can locate the Cloud Connector behind a web proxy for monitoring its outbound Internet communications. However, the web proxy must work with SSL/TLS encrypted communication.

The Cloud Connector might have more outbound ports with access to the Internet. The Cloud Connector negotiates across a wide range of ports to optimize network bandwidth and performance if more ports are available.

The Cloud Connector must have a wide range of inbound and outbound ports open within the internal network. The table below lists the base set of open ports required.

Each of the services used within Citrix Cloud Government extends the list of open ports required. For more information, consult Connectivity requirements for Citrix Cloud Government.

Monitoring outbound communication

The Cloud Connector communicates outbound to the Internet on port 443, both to Citrix Cloud Government servers and to Microsoft Azure Service Bus servers.

The Cloud Connector communicates with domain controllers on the local network that are inside the Active Directory forest where the machines hosting the Cloud Connector reside.

During normal operation, the Cloud Connector communicates only with domain controllers in domains that are listed as Use for subscriptions on the Identity and Access Management page in the Citrix Cloud Government user interface.

In selecting the domains to configure as Use for subscriptions, the Cloud Connector communicates with domain controllers in all domains in the Active Directory forest where the machines hosting the Cloud Connector reside.

Each service within Citrix Cloud Government extends the list of servers and internal resources that the Cloud Connector might contact during normal operations. Also, customers cannot control the data that the Cloud Connector sends to Citrix. For more information about services’ internal resources and data sent to Citrix, consult Connectivity Requirements.

Viewing Cloud Connector logs

Any information relevant or actionable to an administrator is available in the Windows Event Log on the Cloud Connector machine.

View the installation logs for the Cloud Connector in the following directories:

• %AppData%\Local\Temp\CitrixLogs\CloudServicesSetup
• %windir%\Temp\CitrixLogs\CloudServicesSetup

Logs of what the Cloud Connector sends to the cloud are found in %ProgramData%\Citrix\WorkspaceCloud\Logs.

The logs in the WorkspaceCloud\Logs directory are deleted when they exceed a specified size threshold. The administrator can control this size threshold by adjusting the registry key value for HKEY\_LOCAL\_MACHINE\\SOFTWARE\\Citrix\\CloudServices\\AgentAdministration\\MaximumLogSpaceMegabytes.

SSL/TLS Configuration

The base Cloud Connector configuration does not need any special SSL/TLS configuration.

The Cloud Connector must trust the certification authority (CA) used by Citrix Cloud Government SSL/TLS certificates and by Microsoft Azure Service Bus SSL/TLS certificates. Citrix and Microsoft might change certificates and CAs in the future. But Cloud Connector always uses CAs that are part of the standard Windows Trusted Publisher list.

Each service within Citrix Cloud Government has different SSL configuration requirements. For more information, consult the Technical Security Overview for each service (listed at the beginning of this article).

Connector updates

When Citrix software updates are available, the Cloud Connector self-manages. Do not disable reboots or put other restrictions on the Cloud Connector. These actions prevent the Cloud Connector from updating itself when there is a critical update.

The customer is not required to take any other action to react to security issues. The Cloud Connector automatically applies any security fixes and updates for Citrix software.

Guidance for handling compromised accounts

• Audit the list of administrators in Citrix Cloud Government and remove any who are not trusted.
• Disable any compromised accounts within your company’s Active Directory.
• Contact Citrix and request rotating the authorization secrets stored for all the customer’s Cloud Connectors. Depending on the severity of the breach, take the following actions:
  • Low Risk: Citrix can rotate the secrets over time. The Cloud Connectors continue to function normally. The old authorization secrets become invalid in 2-4 weeks. Monitor the Cloud Connector during this time to ensure that there are no unexpected operations.
  • Ongoing high risk: Citrix can revoke all old secrets. The existing Cloud Connectors will no longer function. To resume normal operation, the customer must uninstall and reinstall the Cloud Connector on all applicable machines.