Certificate Authentication Provider - SSO

Owned by ubisebastian
2022-01-16

This page describes the Ubisecure Certificate Authentication Provider and how it is used with the Ubisecure Authentication Server to create extensible authentication systems.

Ubisecure Certificate Authentication Provider is a standalone SAML IdP that performs client certificate authentication. This allows users to authenticate using browser-based client certificates or integrate with smart-card based client certificates. It is configured as an Authentication Method of the Ubisecure Authentication Server. 

Ubisecure Certificate Authentication Provider is a standard Java Servlet web application deployed on a pre-configured standalone Apache Tomcat application server that is included in the distribution package.

Certificate Authentication Provider Functionality

Client certificate or smart card authentication is based on asymmetric authentication on SSL or TLS connections. During the authentication process the client sends an X.509 certificate to the server. The server is required to perform a set of validation tasks on the certificate, based on the defined PKI policy before the certificate presented by the client is accepted for authentication.

The Ubisecure Certificate Authentication Provider implements client certificate authentication. It is the responsibility of the Authentication Provider to implement all required validation tasks on the certificate before the Authentication Provider is allowed to forward the authenticated identity to Ubisecure Server.

The standard process flow is shown in Figure 4 and described below:

  1. A user attempts to access resource /webapp/resource for the first time. The user has no valid existing session.
  2. SAML SP creates a SAML AuthnRequest and redirects the user to UAS
  3. UAS optionally presents the authentication selection method menu if more than one authentication method is permitted for this SP
  4. UAS generates SAML AuthnRequest and redirects user to Certificate Authentication Provider
  5. Certificate Authentication Provider requests Client Certificate from Browser using Two-Way SSL. Depending on browser used and client software installed, user may be prompted to select a certificate and enter a corresponding PIN. For Finnish Identity Cards, this software is provided by Väestörekisterikeskus.
  6. If a certificate is received that matches the policy.xml defined, a Certificate Revocation List check is performed using a HTTP request or LDAP query to the CRL or OCSP server defined in the Certificate Authentication Provider's policy.xml configuration file.
  7. If the CRL/OCSP check is successful, Certificate Authentication Provider creates a SAML Response and redirects the user to UAS for further authentication and authorization. Attributes from the client certificate are sent according to the settings in the Certificate Authentication Provider's policy.xml configuration file.
  8. The SAML Response is sent from Certificate Authentication Provider to UAS.
  9. UAS performs the standard user authorization and access control process.
  10. UAS sends a SAML Response to the SAML SP, identifying the user and attributes according to the Authorization Policy selected for that specific SP.
  11. SAML SP redirects the user to the desired resource /webapp/resource.

Figure 4. Certificate Authentication Provider Process Flow


Ubisecure Single Sign-On

The Ubisecure Single Sign-On software product provides a web access management solution that enables access management and single sign-on user authentication using a wide selection of authentication methods, for example: username and password, One-Time Passwords, smart card (or other client certificate), or GSM short messages (plain text or signed). 
The key functionality of Ubisecure Single Sign-On is to offer access management and related services for web applications with a selection of authentication methods to best serve the needs of the application or user level in question.

Ubisecure Single Sign-On Authentication Process

Figure 1. The Ubisecure Single Sign-On authentication and single sign-on process with Web Application
  1. The user makes a request with his browser to a restricted web application.
  2. The Ubisecure Web Application intercepts the request because no valid credentials are included in the request. The Web Application creates a ticket request and redirects the request to the Ubisecure Authentication Server (UAS).
  3. The browser forwards the ticket request to UAS. UAS validates the ticket request and starts the authentication process.
  4. Authentication process. SSO functionality: If the user has a valid existing session with UAS then the authentication process is skipped.
  5. When the user has been authenticated, UAS creates a ticket response and redirects the browser back to the web application. UAS also creates an authentication session with the user.
  6. The browser repeats the initial request to the web application, now with a ticket response included.
  7. The Web Application validates the ticket response and allows the request to get through to the web application.

Ubisecure Authentication Server authenticates users, implements access control and sends authentication information in encrypted format to Ubisecure Web Applications. The Ubisecure Web Application deciphers and validates authentication information received from the Authentication Server and allows validated requests to get through to the web application. The Web Application also passes information about the authenticated identity to the web application.

Ubisecure Authentication Providers

Ubisecure Authentication Providers extend the available authentication methods available to Ubisecure Authentication Server (UAS) in cases where authentication must be performed on a different network or platform. There are four types of Ubisecure Authentication Providers:

  1. Windows Authentication Provider
  2. Certificate Authentication Provider
  3. Http Header Authentication Provider
  4. Custom Authentication Provider

Ubisecure Authentication Provider Authentication Process

Ubisecure Authentication Server and an Authentication Provider interoperate in a similar way to Ubisecure Authentication Server and a Web Application. All communication between UAS and the Authentication Provider is done through browser redirects.
Figure 1 gives an overview of the authentication process where a Web Application requests authentication services from the Ubisecure Authentication Server. With the Authentication Providers the roles are reversed:

  • The Ubisecure Authentication Server takes the role of a Web Application.

  • The Authentication Provider takes the role of an Ubisecure Authentication Server.

    Figure 2. The Ubisecure authentication process with an Authentication Provider

  1. The browser has been redirected from a Web Application to UAS with a ticket request.
  2. The user selects an authentication method involving an Authentication Provider. The UAS creates an authentication request and redirects the browser to the Authentication Provider.
  3. The browser forwards the authentication request to the Authentication Provider. The Authentication Provider validates the authentication request and starts the authentication process.
  4. Authentication process.
  5. The Authentication Provider creates an authentication response and redirects the browser back to UAS.
  6. The browser forwards the authentication response to UAS
  7. UAS validates the authentication response and creates a ticket response for the Web Application that initially started the process. UAS also creates an authentication session with the user.

Although the functionality provided by the Authentication Provider is very similar to the functionality provided by UAS, there are however some key differences:

  • The Authentication Provider generally does not start a session with the browser and therefore does not provide single sign-on functionality. Single sign-on is implemented by UAS.
  • The Authentication Provider does not implement access control. UAS implements access control for the Web Applications.
  • The Authentication Provider generally provides services for a single authentication server whereas the authentication server provides services for an unlimited number of Web Applications.

Deployment

The Authentication Provider architecture makes it possible to install UAS and the Authentication Provider on disconnected networks. Only the user's browser needs to connect to both servers. No direct connection between Ubisecure Authentication Server and the server running Ubisecure Authentication Provider is required. This possibility enables very advanced scenarios.

Windows Authentication Providers

Some authentication protocols, such as the Windows Integrated protocol with Internet Explorer or Firefox, are only enabled for Intranet use, because they require that the client computer is on the same Active Directory domain. With Ubisecure solution, it is possible to install a Windows Authentication Provider on the Intranet even if the Ubisecure Authentication Server is connected to the Internet.

Organization to Organization Authentication Providers

Figure 3. Advanced Authentication Provider deployment scenario

  • The users at Organization A authenticate locally on the Intranet to a Windows Active Directory
  • This authentication information is forwarded by the Ubisecure Authentication Provider to Ubisecure Authentication Server
  • The result is that the Extranet Site at Organization B allows transparent and seamless authenticated access for users from Organization A

Identity Mappings

The Authentication Provider passes the name of the authenticated identity to UAS. UAS maps this identity to a Ubisecure identity. UAS manages separate identity mappings for each Authentication Provider.
After a Ubisecure identity is established all normal access control features of Ubisecure Authentication Server are applied.

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