Principal Archive – Deyda.net

SAML Authentication between Citrix & Microsoft with Azure MFA

Update to the latest cloud navigation.

As a result of increasing projects, here is a little how-to with the summary of my previous articles. The main points are:

Azure AD Seamless Single Sign-On (PTA / PHS)
SAML Authentication (Azure AD as IdP & Citrix Gateway as SP)
Citrix Federated Authentication Service (FAS)
Microsoft Azure Multi-Factor-Authentication with Conditional Access

Requirements

Fully working Citrix Virtual Apps and Desktop Environment (StoreFront & DDC Minimum Version 7.9)
NetScaler with successful base configuration & activated Enterprise or Platinum license (Minimum Version 12.1 Build 50+ for native workspace app, for browser Minimum Version 11.1)
Configured Unified Gateway vServer
Internal and external DNS entries for Unified Gateway vServer (e.g. citrix.deyda.net)
Certificates for DNS entries (wildcard certificates are the easiest)
Existing Azure Tenant with Azure-AD base configuration (Domain, AAD Sync) & activated Azure AD Premium license
AD Connect version installed and configured (Minimum Version 1.1.644.0)
Firewall release for *.msappproxy.net on port 443
Domain administrator credentials for the domains that connected to Azure AD via AD Connect
Installed Authenticator App on Test User Mobile Phone

SAML Authentication with Azure AD as IdP and Citrix as SP

Since Citrix XenApp / XenDesktop 7.9 the Federated Authentication Service (FAS) is available. Via Citrix FAS it is possible to authenticate a user via SAML and thus connect Citrix as a service provider to existing identity providers, such as Azure-AD.

Sequence of SAML authentication

The user browse the FQDN (e.g. citrix.deyda.net) of the Citrix Gateway vServer (Service Provider) to start his VA / VD resources
The Citrix Gateway vServer directs the unauthenticated user directly to the Identity Provider (Azure-AD) to authenticate itself (saml: authnRequest)
The Identity Provider points to its SingleSignOnService URL (e.g. login.microsoftonline.com) and the user must authenticate
The user enters his AD credentials and these are checked by the Identity Provider against the user database
Upon successful verification in the user database, the IdP is informed
The IdP issues a token (SAML assertion) and sends it to the Citrix Gateway (saml: response)
Citrix Gateway checks the token (assertion signature) and extracts the UPN from the assertion token. This allows access via SSO to the VA / VD farm via FAS (The SP does not have access to the user’s credentials)

SAML Auth Azure AD & Citrix Gateway with FAS

Citrix ADC as AD FS Proxy

This article is about creating an AD FS Proxy from Citrix ADC (version 12). The AD FS Proxy is used to authenticate e.g. external SaaS applications or websites via AD FS. The following should be achieved by the AD FS Proxy:

URL / DoS Protection
Suitable external authentication (MFA, Forms instead of Kerberos)
Account Lockout Protection
Availability (Load Balancing)

What is AD FS ?

Active Directory Federation Services (AD FS) is a feature in the Windows Server operating system that allows identity information to be shared outside of the corporate network. Users can access applications (e.g. Office365, Salesforce.com, etc.) without being prompted to provide credentials again. These applications can be hosted locally, in the cloud, or even by other companies. The user accounts can be managed by the administrator in a single location, the Active Directory.

A normal deployment of AD FS for external clients consists of AD FS Proxy and AD FS Server. The AD FS Server is a member of the domain and perform the authentication. The AD FS Proxy is usually located in a separate network zone (DMZ) so that it can be reached externally and forward the requests inwards.

Citrix ADC as initial IdP for Office365

This article is about setting up SAML authentication for Office365 through the Citrix ADC (version 12). The Citrix ADC serves as IdP and Office365 as SP. So that you do not have to enter your user name a hundred times, this is prevented by an initial IdP (SSO).

Terminology

In short, the important upcoming terms explained.

SAML

SAML (Security Assertion Markup Language) provides a common platform for web-based access to multiple, autonomous services without the need to reenter multiple credentials. Authentication takes place via an encrypted session cookie, transparent in the background. This session cookie, which is provided with an expiration date, is given to the user in the browser by an authentication service (Identity Provider – IdP) and can then subsequently use all connected services (Service Provider – SP) in the browser.