Virtualization, technology, and random rantings with a focus on Citrix and VMware.

Category: Netscaler

How To Create The Wow nFactor!

nFactor Flow

This will end up being my first foray into a multi-part series. I will post the links to the other relevant walk throughs as I complete them.

Part 2 of the configuration:

This configuration covers setting up EULA as a first factor in an nFactor flow to do one side of an MFA configuration. This will setup a group extraction that looks for an assigned Universal group that is designated to trigger directing traffic to an MFA provider. The reason for using a Universal group would be in an instance where you have a forest with multiple subdomains that have a two-way transitive trust. This allows you to manage group membership from one domain as the Universal group will be replicated to all the domain controllers. This example is to check membership of the Universal group and perform cascading LDAP for the users that are NOT members of that Universal group.

So I was trying to move to advanced authentication in a test environment. While I was doing that, I thought to myself that since my end goal with that test, would be to prep to move to MFA. That led to me thinking how I would want to implement that. Then…… I ran into a very interesting thing when you move from using basic authentication to an authentication profile with AAA-TM, that the EULA option goes bye bye. There isn’t even an option to select. So I went looking how to resolve that. One option was to follow a guide that I found to edit some xml files, but that meant that I would have to manually copy these to keep them in sync between the Citrix ADCs. I didn’t like that idea but did see the option to use EULA as a first factor in nFactor. Hmm… I was already thinking in that mode to setup nFactor since it would be needed to go down the MFA road. So that is the decision I decided to work on and get testing. I also found some interesting tidbits that I’ll point out in the configuration.

Update: Changed LDAPS policy settings to fix “Anonymous” issue.

Update: Added link to article to create custom XML file to change ${} to ${AAA.USER.NAME}

So here we go!

You will need to have either Advanced or Premium license to have access to this feature. You will also need to have configured an Authentication Virtual Server which I will link soon.

Login to you Citrix ADC.

Navigate to Security > AAA – Application Traffic > nFactor Visualizer > nFactor Flows.

Select Add.

Select the “+” in the center of the square.

Select “Create Factor.”

Enter “Factor Name.”

Click “Create.”

Select “Add Schema.”

Enter “Name” for schema.

In the “Authentication Schema” box, select the “Edit” pencil.

Click on the “LoginSchema.” This will bring up a list to choose from.

Scroll down and select “Eula.xml.”

Click the “Edit” button if you want to edit the EULA message.

After you change the EULA message below and click “Save,” click the “Select” button. This is VERY important or it won’t select it.

After you have configured the message, click “Save.”

Click “Create” button.

Click “OK.”

Click on “Add Policy.”

Click the “Add” button.

Name the policy and select “Action” as “NO_AUTHN.”

For the “Expression,” enter “HHTP.REQ.URL.CONTAINS(“/nf/auth/”)

Click “OK.”

Click “+” sign beside “NO_Authn_Pol” (whatever you name the Authentication Policy).

Select “Create Factor.” This factor will do the group extraction to test group access.

Name “Factor Name.” (Grp_Ext_Test in this example)

Select “Add Schema.”

Select “Only_User_Name.” This will have the user enter their user name to be evaluated.

Click “OK.”

Click “Add Policy.”

Click “Add.”

Enter “Name” for policy (test-ldap-grpexpt-pol in this example).

Select “Action Type” as “LDAP.”

For the “Expression” enter “true.”

Click “Add” on “Action.”

Select the root of the forest (domain if you only have 1 domain) for the “Server Name.” (The DC that you are trying to access will need to have the Global Catalog available for this to work correctly)

For the “Port,” choose either 3268 for unsecure LDAP or 3269 for secure LDAP (This will require that you upload the root certificate for the organization to utilize).

Make sure the UNCHECK the box for Authentication. This is just going to do a lookup if the user is part of the MFA group.

Enter your “Base DN” as where the users will be or the root of the forest / domain.

Enter “Administrator Bind DN” which is the account that will authenticate to the domain.

Enter and confirm “Administrator Password.”

Click “Test Network connectivity” to make sure that it is working correctly.

Complete “Server Logon Name Attribute” as “sAMAccountName.” The samaccountnames need to be unique in the forest or you will have issues with this global catalog lookup.

For “Group Attribute” select “memberOf.”

For “Sub Attribute Name” select “cn.”

Click the “+” sign beside “test-ldap-grpext-pol.”

Select “Create decision block” and enter “Decision block Name.” (Grp_Eval_Test in this example)

Click “Create.”

Click “Add Policy.”

Click “Add.” (NonMFA_Test in this example)

Select “Action Type” as “N0_AUTHN.”

Select “Action” as “NO_AUTHN.”

In the “Expression” enter “AAA.USER.IS_MEMBEROF(“UniversalGroup”).NOT.” (UniversalGroup is the group name of the MFA testing group)

Click on the “+” sign beside “NonMFA_Test.”

Select “Create Factor.”

Enter “Factor Name.” (LDAPS_Auth_Test in this example)

Click “Create.”

For the “Authentication Schema” click the pencil icon.

This allows you to take what was entered just after click on “Continue” for the EULA and populating that in the User Name / Password dialogue to prevent users from having to enter it twice.

Under the “Login Schema Files” select “PrefilUserFromExpr.xml. (Note that User Name contains $(

Click “Select.”

Click “Create.”

This error will pop up and you have to click “OK.” It will still work. This is the link to the remediation of this:

Click “OK.”

Click “Add Policy.”

Enter “Name.” (test-auth-pol in this example)

Under “Action Type” select “LDAP.”

For “Action” select existing LDAP/LDAPS server.

For “Expression” enter “true.”

You can click the “+” sign on the bottom of the box to add additional LDAP/LDAPS policies. This is what you would normally see under the Basic Authentication on the Citrix Gateway.

Once you have completed this, you will need to go the appropriate Citrix Gateway vServer and change the authentication. Next step to adding nFactor and using Advanced Authentication:

EULA Evolves, Form Of nFactor!

Preview of what is coming this weekend…..

nFactor Overview

How about a way to convert basic authentication on Citrix Gateway on-prem to advanced authentication with nFactor.

Responder To The Log4

Make sure and keep up to date from Citrix with the CVE-2021-44228.

This link has the mitigations for the WAF and a Responder policy.

Page 2 of 2

Powered by WordPress & Theme by Anders Norén