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Smart Card Single Sign
On with Access
Gateway Enterprise
Edition
Nicolas Ogor, Escalation Engineer.
06/10/10
Agenda
• Introduction of Access Gateway Enterprise Edition.
• What's new in Web Interface 5.3 ?
• Configuration.
• Limitations and solutions.
• Troubleshooting.
Introduction to Access Gateway
Enterprise Edition
• Combine your traditional IPSec VPN and Secure Gateway into a single
appliance.
• Easy to configure with XenApp and XenDesktop.
• Support up to 10,000 concurrent connections.
• Physical and Virtual version available.
What's new in Web Interface 5.3 ?
New enhancements and features in this release
• Pass-through with smart card from the Access Gateway.
• Support for 32-bit color.
• XenApp farm migration.
• Multiple launch prevention.
• Support for Windows Server 2008 R2.
How does the Pass-through work ?
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
How does the Pass-through work ?
AGEE
Domain Controller
User
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
Domain Controller
AGEE
Certificate validation
User
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
User
Domain Controller
Citrix AGBasic
No password
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
Local PTS service
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
Username and Domain name
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
S4U
User
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
.NET WindowsIdentity class
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
.NET WindowsIdentity class
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
Web Interface
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
XML
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
Application list
XenApp
How does the Pass-through work ?
AGEE
Domain Controller
User
HTTPS
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
How does the Pass-through work ?
AGEE
User
Domain Controller
HTTPS
• Web Interface uses the
Protocol Transition Service with
the User and domain name
parameters to obtain an
instance of the .NET
WindowsIdentity class from the
Domain Controller.
• This .NET object represents
the user’s logon session. This
is used to create a
WindowsToken that can
authenticate the user.
Web Interface
XenApp
Configuration
Certificate Authority
• Install a Certificate Authority in the domain.
• Open MMC-select Certificate Authority and
Certificate template.
•
Duplicate the Smart card logon template.
•
Select your CSP.
Certificate Authority
• Issue the Certificate template created previously to be available for users.
Client computer
• Install your CSP software on your computer.
• Logon to your Certificate Authority.
• Select the Certificate template and CSP
vendor.
• The certificate will be installed into the smart
card.
XenApp and Web Interface requirements
• XenApp and Web Interface servers must be domain members.
• XenApp XML service must be running with IIS on servers chosen as XML
brokers and STA servers
• XenApp version 4.5 and 5 are currently supported.
• Web Interface 5.3 or later must be used.
• Active Directory domain functional level must be 2003 or 2008.
Setup delegation on your domain
•Delegation definition: Some server services require access to a second server.
In order to establish a session with the second server, the primary server must be authenticated
on behalf of the client's user account and authority level.
Setup delegation on your domain
Setup delegation on your domain
1 - Client provides credentials and domain
controller returns a Kerberos TGT to the
client.
Setup delegation on your domain
2 - Client uses TGT to request a service
ticket to connect to Server 1.
Setup delegation on your domain
3 - Client connects to Server 1 and provides
both TGT and service ticket.
Setup delegation on your domain
4 - Server 1 uses the clients TGT to request
a service ticket so Server 1 can connect to
Server 2 .
Setup delegation on your domain
5 - Server 1 connects to Server 2 using the
client’s credentials.
Setup delegation on your domain
• Web Interface must delegate http service
to the XML broker.
Setup delegation on your domain
• XML
broker must delegate the http service
to itself and host services to all XenApp
servers in the farm.
Setup delegation on your domain
• Each XenApp server must delegate cifs and ldap services
to the Domain Controllers and host services to itself and http
services to the XML broker.
Access Gateway configuration
• Create a Virtual Server and associate a server certificate.
• Bind the root certificate as a Root Certificate Authority on the Virtual server.
Access Gateway configuration
• Enable client authentication and client
certificate to optional on the Virtual
server properties.
Access Gateway configuration
• Create an authentication profile of type certificate.
• Under the User Name field specify the certificate attribute to extract.
Access Gateway configuration
• Create a session profile that will redirect
users to the Web Interface after
successful authentication.
• Specify the NetBIOS name of your
domain for the Single Sign- on domain.
• Bind the session profile to your Virtual
server.
Web Interface Site
• Install a server certificate on
the Web Server.
• Create a site and specify the
path of the Web site.
Web Interface Site
• Set the Authentication to take place
at the Access Gateway and select
the option “Enable Smart Cardpass-through”.
Web Interface Site
• Once the site is created , you must
restart your Web Interface server.
Web Interface Site
• Specify your XML broker.
Web Interface Site
• Finish the Web Interface site
configuration and restart the Web
Interface server.
Web Interface Site
• Check if the Protocol Transition Service is running.
Web Interface Site
• Configure the Secure Access to go
through the Gateway.
Web Interface Site
• Specify the FQDN of your Access
Gateway Virtual Server.
Web Interface Site
• Specify the Secure Ticket Authority
servers on the Web Interface and
AGEE.
Limitations and solutions
PIN prompt when launching a Published Application
• Cause : User receives a Pin prompt
when hitting the AGEE Virtual server
with the ICA client because the option
Client Certificate is On.
PIN prompt when launching a Published Application
• Solution : Create another Virtual server with same IP address, certificate but a
different port and with the option Client certificate set to off.
• On Vserver binds the STA server specified on the Web Interface site.
• Create a dummy authentication policy and bind it to the Vserver to avoid users to
logon directly to that Virtual server.
PIN prompt when launching a Published Application
• Solution : On the Secure Access
Settings of the Web Interface specify
the new Virtual Server.
• All HTTP traffic will now go through the
VIP on port 443 and ICA proxy traffic
through port 444.
Limitations of Kerberos Pass-through Authentication
• Issue: Applications running on XenApp that
depend on the NTLM protocol for
authentication generate explicit user
authentication prompts or fail because the
password is never sent over the network.
• Workaround: Configure delegation on the
targeted servers to use Kerberos instead of
NTLM authentication.
Limitations of Kerberos Pass-through Authentication
• Issue: Kerberos pass-through authentication for
applications expires if the XenApp session is left running
for a very long time (typically one week) without being
disconnected and reconnected.
• Workaround: You have to force user to disconnect after
the Kerberos ticket expired.
Troubleshooting
Decrypt traffic between the Web Interface and AGEE
• Install Wireshark tool or other networking sniffer on the Web Interface server.
• Retrieve private keys for the Web Interface certificate and the AGEE virtual
server certificate.
• Configure Wireshark SSL preferences to use the Private keys to decrypt
traffic. ( http://support.citrix.com/article/CTX116557 )
• Start a trace on the Web Interface server.
Authentication process
1. The client opens a Web browser and enters a URL.
2. The user presents the client certificate to the portal page and clicks Logon.
3. AGEE extracts the username from the certificate.
4. Client sends a GET request to the home page defined on the global SSL VPN settings, or a session profile.
This communication is client to VIP.
5. AGEE sends the same GET to the Web Interface page called login.aspx.
6. Web Interface issue a 302 Found message with a redirect to agesso.aspx.
Authentication process
7. Client sends a GET for agesso.aspx to the VIP and the appliance then forward it to Web Interface.
8. Web Interface responds with a 401 Unauthorized message including a header named WWW-Authenticate which
should have CitrixAGBasic password_required="No" as its value as well as a ticket ID.
Authentication process
9. After the 401 unauthorized message, the
appliance sends another GET for agesso.aspx
including an authorization.
This header includes a hash value of the user
name, domain and session ID.
Web Interface responds by a 302 and set the
cookie WIAuthID.
Authentication process
10. This now causes the Web Interface to POST to the
authentication service URL on its configuration.
11. If everything succeed the appliance responds with a
HTTP 200 message and a SOAP envelope containing
the smart access farm name, client IP address, and a
success status code.
Authentication process
12. GET request is sent for default.aspx from the
client (client to VIP). GET request contains the
cookie WIAuthID and the Authorization header which
is a Hash of the username and domain.
Authentication process
13. The Web Interface will contact the XML
broker to get the application list by sending a
Post request to the CtxIntegrated/wpnbr.dll
Authentication process
14. The XML broker will return the published
application list for user to the Web Interface.
15. The Web Interface will respond to the GET
request in step 12 by a 200 response and the
application will be enumerated into the client’s
browser.
Check list
• Take a Network trace on the Web Interface.
• Check application Eventviewer on the Web Interface.
• Check your delegation settings on your Active Directory.
• Ensure that the trust XML request option on the XML
broker is selected.
• Ensure that the root certificate used to sign the AGEE
Virtual server is stored on the Trusted root Certificate
store of the Web Interface server.
• Ensure that the Web Interface can resolve the FQDN
name of the Virtual server.
Before you leave…
• Recommended related breakout sessions:
• SUM502 - XenApp and XenDesktop authentication (Lalit Kaushal)
• Session surveys are available online at www.citrixsynergy.com
starting Thursday, 7 October
• Provide your feedback and pick up a complimentary gift card at the registration desk
• Download presentations starting Friday, 15 October, from your My
Organiser Tool located in your My Synergy Microsite event account