Linux PAM Integration with AuthPoint

Contents

Deployment Overview

This document describes how to set up multi-factor authentication (MFA) for Linux PAM with AuthPoint. Linux PAM must already be configured and deployed before you set up MFA with AuthPoint.

Your Linux can be configured to support MFA in several modes. For this integration, we set up RADIUS authentication with AuthPoint. RADIUS authentication requires that you install the AuthPoint Gateway on your network, which functions as a RADIUS server.

This integration was tested with Ubuntu 22.04 LTS.

Linux PAM Authentication Data Flow with AuthPoint

AuthPoint communicates with various cloud-based services and service providers with the Radius protocol. This diagram shows the data flow of an MFA transaction for Linux.

Topology diagram

Before You Begin

Before you begin these procedures, make sure that:

  • You have installed and configured the AuthPoint Gateway (see About Gateways)
  • A token is assigned to a user in AuthPoint

Configure Ubuntu 22.04 LTS

  1. Log in to your Linux server as a root user.
  2. Type $ sudo apt-get install libpam-radius-auth and press Enter to install PAM with Radius Authentication Module.
  3. Edit the /etc/ssh/sshd_config file to enable PAM authentication in the ssh service. Make sure KbdInteractiveAuthentication yes is enabled and does not include a #.
  4. Edit the /etc/ssh/sshd_config file to ensure that UsePAM yes is enabled and does not include a #.
  5. Save and quit.
  6. Edit the /etc/pam.d/sshd file and add the line auth sufficient pam_radius_auth.so at the beginning of the file to enable PAM with Radius in the PAM module. Make sure you comment out the @include common-auth line.
  7. Save and quit.
  8. Edit the /etc/pam_radius_auth.conf file and comment out the default 4 lines.

    9. Screenshot of PAM, comment out the default 4 lines in the pam_radius_auth.conf file

  9. Edit the /etc/pam_radius_auth.conf file and add a line that specifies the IP address of the RADIUS server (AuthPoint Gateway) and shared secret.

    10. For example, add a line without specifying the vrf field and the source_ip field.

    Screenshot of PAM, add a line to the pam_radius_auth.conf file

    If you want to specify the vrf field and the source_ip field, you should create a VRF device with an associated route table, and assign a network interface to the VRF. For more information about how to create VRF, refer to Virtual Routing and Forwarding (VRF).

    After you have created a VRF, you can use the command $ ip -br link show type vrf to list the VRF, and the command $ ip -br link show vrf <vrf name> to display the device assigned to the VRF.

    Screenshot of PAM, commands to list the vrf and device assigned to the vrf

    Refer to the screenshot below for an example of a line that specifies the vrf field and the source_ip field.

    Screenshot of PAM, add a line to the pam_radius_auth.conf file with vrf field configured

  10. Save and quit.
  11. Add the configuration folder:
    1. Type $ sudo mkdir /etc/raddb and press Enter.
    2. Type $ sudo cp /etc/pam_radius_auth.conf /etc/raddb/server and press Enter.
  12. Type $ sudo service ssh restart and press Enter to restart the ssh service.
  13. Type $ sudo adduser <user name> and press Enter to create a user on the Linux server. You must create a user with the same user name in AuthPoint.

Configure AuthPoint

Before AuthPoint can receive authentication requests from Linux PAM, you must:

Add a Radius Resource in AuthPoint

From the AuthPoint management UI:

  1. From the navigation menu, select Resources. Click Add Resource.
    The Add Resource page opens.

  1. From the Type drop-down list, select RADIUS Client.
    Additional fields appear.

  1. In the Name text box, type a descriptive name for the resource.
  2. In the RADIUS client trusted IP or FQDN text box, type the IP address that your RADIUS client uses to send RADIUS packets to the AuthPoint Gateway. This must be a private IP address. If you specified the vrf field in the previous section, this address is the IP address of the network interface assigned to the VRF device.
  3. From the Value sent for RADIUS attribute 11 drop-down list, specify what is sent for the attribute 11 (Filter-ID) value in RADIUS responses. You can choose to send the user's AuthPoint group or the user's Active Directory groups.
  4. In the Shared Secret text box, type the shared secret key. This is the password that the RADIUS server (AuthPoint Gateway) and the RADIUS client (Linux Server) will use to communicate.
  5. Click Save.

Add a Group in AuthPoint

You must have at least one user group in AuthPoint to configure MFA. If you already have a group, you do not have to add another group.

To add a group to AuthPoint:

  1. From the navigation menu, select Groups.
  2. Click Add Group.
    The New Group page appears.

Screenshot that shows the Groups page.

  1. In the Name text box, type a descriptive name for the group.
  2. (Optional) In the Description text box, type a description of the group.

Screen shot of the New Group page.

  1. Click Save.
    Your group is listed on the Groups page.

Screenshot of the Save button on the New Group page.

Add an Authentication Policy to AuthPoint

Authentication policies specify which resources users can authenticate to and which authentication methods they can use (Push, QR code, and OTP).

You must have at least one authentication policy in AuthPoint that includes the Linux PAM RADIUS client resource. If you already have authentication policies, you do not have to create a new authentication policy. You can add this resource to your existing authentication policies.

Users that do not have an authentication policy for a specific resource cannot authenticate to log in to that resource.

For the Linux PAM RADIUS client resource, you must select the password authentication option in your authentication policies.

To configure an authentication policy:

  1. From the navigation menu, select Authentication Policies.
    The Authentication Policies page opens.

Screenshot of the Add Policy button on the Authentication Policies page.

  1. Click Add Policy.
    The Add Policy page opens.

  1. In the Name text box, type a name for this policy.
  2. From the Select the Authentication Options drop-down list, select Authentication Options, then select which authentication options users can choose from when they authenticate.

    If you enable the push and OTP authentication methods for a policy, RADIUS client resources associated with that policy use push notifications to authenticate users.

    QR code authentication is not supported for RADIUS client resources.

  3. From the Groups drop-down list, select which groups this policy applies to. You can select more than one group. To configure this policy to apply to all groups, select All Groups.
  4. From the Resources drop-down list, select the resource that you created in the previous section. If you want this policy to apply to additional resources, select each resource this policy applies to. To configure this policy to apply to all resources, select All Resources.

Screenshot of the Add Policy page with the groups and resources selected

  1. (Optional) If you have configured policy objects such as a Network Location, select which policy objects apply to this policy. When you add a policy object to a policy, the policy only applies to user authentications that match the conditions of the policy objects. For example, if you add a Network Location to a policy, the policy only applies to user authentications that come from that Network Location. Users who only have a policy that includes a Network Location do not get access to the resource when they authenticate outside of that Network Location (because they do not have a policy that applies, not because authentication is denied).

    For RADIUS authentication, policies that have a Network Location do not apply because AuthPoint does not have the IP address of the user.

    If you configure policy objects, we recommend that you create a second policy for the same groups and resources without the policy objects. The policy with the policy objects should have a higher priority.

Screenshot of the Policy Objects drop-down list.

  1. Click Save.
    Your policy is created and added to the end of the policy list.

    When you create a new policy, we recommend that you review the order of your policies. AuthPoint always adds new policies to the end of the policy list.

Bind the RADIUS Resource to a Gateway

To use RADIUS authentication with AuthPoint, you must have the AuthPoint Gateway installed on your corporate network and you must assign your RADIUS resources to the Gateway in the AuthPoint web UI. The Gateway functions as a RADIUS server.

If you have not configured and installed the AuthPoint Gateway, see About Gateways.

  1. From the navigation menu, select Gateway.
  2. Select the Name of the Gateway.

  3. From the RADIUS section, in the Port text box, type the port number used to communicate with the Gateway. The default ports are 1812 and 1645.

    If you already have a RADIUS server installed that uses port 1812 or 1645, you must use a different port for the AuthPoint Gateway.

  4. From the Select a RADIUS Resource drop-down list, select your RADIUS client resource.
  5. Click Save.

Add Users to AuthPoint

Before you assign users to a group, you must add the users to AuthPoint. There are two ways to add AuthPoint user accounts:

  • Sync users from an external user database
  • Add local AuthPoint users

Each user must be a member of a group. You must add at least one group before you can add users to AuthPoint.

To import users from Active Directory, Microsoft Entra ID, or an LDAP database, you must add an external identity in the AuthPoint management UI. External identities connect to user databases to get user account information and validate passwords.

  • To sync users from Active Directory or an LDAP database, you must add an LDAP external identity
  • To sync users from Microsoft Entra ID, you must add a Microsoft Entra ID external identity

When you sync users from an external user database, you can sync any number of users and they are all added to AuthPoint at one time. Users synced from an external user database use the password defined for their user account as their AuthPoint password.

To learn how to sync users, go to Sync Users from Active Directory or LDAP and Sync Users from Azure Active Directory.

You can create local AuthPoint users on the Users page in the AuthPoint management UI. Because you can create only one user at a time, you most commonly do this when you want to create test users or to add only a small number of users.

Unlike users synced from an external user database, local AuthPoint users define and manage their own AuthPoint password. When you add a local user account, the user receives an email that prompts them to set their password.

To learn how to add local AuthPoint user accounts, go to Add Local AuthPoint Users.

Test the Integration

To test the integration of AuthPoint and the configuration of your Linux, you can authenticate with a mobile token on your mobile device. For RADIUS resources, you can choose a one-time password (OTP) or push.

In this example, we show the push authentication method.

If you want to use the OTP authentication method, the authentication policy for your AuthPoint resource must not allow the push authentication option. If you enable the push and OTP authentication methods for a policy, RADIUS resources associated with the policy use push notifications to authenticate users.

  1. In an SSH client, connect to the Linux server.
  2. Type your AuthPoint password.
  3. Approve the authentication request that is sent to your mobile device.
    You are logged in to Linux.