Security Assertion Markup Language (SAML) is an XML-based authentication mechanism that provides single sign-on capability and is defined by the OASIS Security Services Technical Committee.
Starting from NetScaler 12.0 Build 51.x, Citrix ADC appliance used as a SAML Service Provider (SP) with Multi-Factor (nFactor) authentication now prepopulates the user-name field on the login page. The appliance sends a NameID attribute as part of a SAML authorization request, retrieves the NameID attribute value from the Citrix ADC SAML Identity Provider (IdP), and prepopulates the user-name field.
Why use SAML authentication
Consider a scenario in which a service provider (LargeProvider) hosts a number of applications for a customer (BigCompany). BigCompany has users that must seamlessly access these applications. In a traditional setup, LargeProvider would need to maintain a database of users of BigCompany. This raises some concerns for each of the following stakeholders:
- LargeProvider must ensure security of user data.
- BigCompany must validate the users and keep the user data up-to-date, not just in its own database, but also in the user database maintained by LargeProvider. For example, a user removed from the BigCompany database must also be removed from the LargeProvider database.
- A user has to log on individually to each of the hosted applications.
The SAML authentication mechanism provides an alternative approach. The following deployment diagram shows how SAML works (SP initiated flow).
The concerns raised by traditional authentication mechanisms are resolved as follows:
- LargeProvider does not have to maintain a database for BigCompany users. Freed from identity management, LargeProvider can concentrate on providing better services.
- BigCompany does not bear the burden of making sure the LargeProvider user database is kept in sync with its own user database.
- A user can log on once, to one application hosted on LargeProvider, and be automatically logged on to the other applications that are hosted there.
The Citrix ADC appliance can be deployed as a SAML Service Provider (SP) and a SAML Identity Provider (IdP). Read through the relevant topics to understand the configurations that must be performed on the Citrix ADC appliance.
A Citrix ADC appliance configured as a SAML service provider can now enforce an audience restriction check. The audience restriction condition evaluates to “Valid” only if the SAML replying party is a member of at least one of the specified audiences.
You can configure a Citrix ADC appliance to parse attributes in SAML assertions as group attributes. Parsing them as group attributes enables the appliance to bind policies to the groups.