Two-Factor Authentication for CyberArk Privileged Account Security

Overview

To integrate Duo with your CyberArk Privileged Account Security Solution, you will need to install a local proxy service on a machine within your network. This Duo proxy server also acts as a RADIUS server — there's usually no need to deploy a separate additional RADIUS server to use Duo.

If you are already running a Duo Authentication Proxy server in your environment, you can generally use that existing host for additional applications, appending the new configuration sections to the current config.

Once configured, Duo sends your users an automatic authentication request via Duo Push notification to a mobile device or phone call after successful primary login.

This configuration doesn't support inline self-service enrollment. You'll need to create your users in Duo ahead of time using one of our other enrollment methods, like directory sync or CSV import. Read the enrollment documentation to learn more.

If you're using LDAP group lookup to assign privileges in CyberArk Privileged Account Security and want to preserve this behavior, we recommend using Duo's LDAP proxy with CyberArk instead of RADIUS.

First Steps

Before moving on to the deployment steps, it's a good idea to familiarize yourself with Duo administration concepts and features like options for applications, and Duo policy settings and how to apply them. You'll need to pre-enroll your users in Duo using one of our available methods before they can log in using this configuration. See all Duo Administrator documentation.

You should already have a working primary authentication configuration for your CyberArk Privileged Account Security Solution users before you begin to deploy Duo.

To integrate Duo with your CyberArk Privileged Account Security Solution, you will need to install a local Duo proxy service on a machine within your network. This Duo proxy server will receive incoming RADIUS requests from your CyberArk Privileged Account Security Solution, contact your existing local LDAP/AD or RADIUS server to perform primary authentication if necessary, and then contact Duo's cloud service for secondary authentication.

If you are already running a Duo Authentication Proxy server in your environment, you can use that existing host for additional applications, appending the new configuration sections to the current config. You don't have to set up a new Authentication Proxy server for each application you create. However, there are some cases where it might make sense for you to deploy a new proxy server for a new application, like if you want to co-locate the Duo proxy with the application it will protect in the same data center.

We recommend the following 64-bit operating systems for the system hosting the Duo Authentication Proxy:

• Windows Server 2016 or later
• CentOS Stream 9 or later
• Fedora 39 or later
• Red Hat Enterprise Linux 7 or later
• Rocky Linux 9 or later
• Ubuntu 20.04 LTS or later
• Debian 11 or later

The Duo End of Sale, Last Date of Support, and End of Life Policy states that Duo does not offer support for integrations running on operating system versions beyond the vendor’s stated Last Date of Support date.

See detailed Authentication Proxy operating system performance recommendations in the Duo Authentication Proxy Reference.

We do not recommend installing the Duo Authentication Proxy on the same Windows server that acts as your Active Directory domain controller or one with the Network Policy Server (NPS) role. If you must co-locate the Duo Authentication Proxy with these services, be prepared to resolve potential LDAP or RADIUS port conflicts between the Duo service and your pre-existing services.

Then you'll need to:

1. Sign up for a Duo account.
2. Log in to the Duo Admin Panel and navigate to Applications → Protect an Application.
3. Locate the entry for CyberArk Privileged Account Security LDAP/RADIUS with a protection type of "2FA" in the applications list. Click Protect to get your integration key, secret key, and API hostname. You'll need this information to complete your setup. See Protecting Applications for more information about protecting applications in Duo and additional application options.

Install the Duo Authentication Proxy

If you will reuse an existing Duo Authentication Proxy server for this new application, you can skip the install steps and go to Configure the Proxy.

The Duo Authentication Proxy can be installed on a physical or virtual host. We recommend a system with at least 1 CPU, 200 MB disk space, and 4 GB RAM (although 1 GB RAM is usually sufficient). See additional Authentication Proxy performance recommendations in the Duo Authentication Proxy Reference.

We do not recommend installing the Duo Authentication Proxy on the same Windows server that acts as your Active Directory domain controller or one with the Network Policy Server (NPS) role. If you must co-locate the Duo Authentication Proxy with these services, be prepared to resolve potential LDAP or RADIUS port conflicts between the Duo service and your pre-existing services.

duoauthproxy-version.exe /S

duoauthproxy-version.exe /S /exclude-auth-proxy-manager

sudo ./duoauthproxy-build/install --install-dir /opt/duoauthproxy --service-user duo_authproxy_svc --log-group duo_authproxy_grp --create-init-script yes

Configure the Proxy

After the installation completes, you will need to configure the proxy.

The Duo Authentication Proxy configuration file is named authproxy.cfg, and is located in the conf subdirectory of the proxy installation. With default installation paths, the proxy configuration file will be located at:

Note that as of v4.0.0, the default file access on Windows for the conf directory is restricted to the built-in Administrators group during installation.

The configuration file is formatted as a simple INI file. Section headings appear as:

[section]

Individual properties beneath a section appear as:

name=value

The Authentication Proxy may include an existing authproxy.cfg with some example content. For the purposes of these instructions, however, you should delete the existing content and start with a blank text file.

Duo Authentication Proxy Manager

The Duo Authentication Proxy Manager is a Windows utility for managing the Authentication Proxy installation on the Windows server where you install the Authentication Proxy. The Proxy Manager comes with Duo Authentication Proxy for Windows version 5.6.0 and later.

The Proxy Manager cannot manage remote Duo Authentication Proxy servers, nor can you install the Proxy Manager as a stand-alone application. There is no Proxy Manager available for Linux. The Proxy Manager only functions as part of a local Duo Authentication Proxy installation on Windows servers.

Learn more about using the Proxy Manager in the Duo Authentication Proxy Reference before you continue.

To launch the Proxy Manager utility:

• Open the Start Menu and go to Duo Security.
• Click the Duo Authentication Proxy Manager icon to launch the application. You must have administrative privileges on the Windows server and accept the prompt for elevation.
• The Proxy Manager launches and automatically opens the %ProgramFiles%\Duo Security Authentication Proxy\conf\authproxy.cfg file for editing.

Use the Proxy Manager editor on the left to make the authproxy.cfg changes in these instructions. As you type into the editor, the Proxy Manager will automatically suggest configuration options. Accepting these suggestions helps make sure you use the correct option syntax.

As you follow the instructions on this page to edit the Authentication Proxy configuration, you can click Validate to verify your changes (output shown on the right).

When you complete the Authentication Proxy configuration steps in this document, you can use the Save button to write your updates to authproxy.cfg, and then use the authproxy.cfg button to start the Authentication Proxy service before continuing on to the next configuration steps.

If you do not use the Proxy Manager to edit your configuration then we recommend using WordPad or another text editor instead of Notepad when editing the config file on Windows.

Configure the Proxy for Your Primary Authenticator

In this step, you'll set up the Proxy's primary authenticator — the system which will validate users' existing passwords. Determine which type of primary authentication you'll be using, and create either an Active Directory/LDAP [ad_client] client section, or a RADIUS [radius_client] section as follows.

Active Directory

Add an [ad_client] section if you'd like to use an Active Directory domain controller (DC) or LDAP-based directory server to perform primary authentication. This section accepts the following options:

Required

search_dn=DC=example,DC=com

Optional

security_group_dn=CN=DuoVPNUsers,OU=Groups,DC=example,DC=com

For example:

[ad_client]
host=1.2.3.4
host_2=1.2.3.5
service_account_username=duoservice
service_account_password=password1
search_dn=DC=example,DC=com
security_group_dn=CN=DuoVPNUsers,OU=Groups,DC=example,DC=com

For advanced Active Directory configuration, see the full Authentication Proxy documentation.

RADIUS

To use RADIUS as your primary authenticator, add a [radius_client] section to the top of your config file. Then add the following properties to the section:

Required

Optional

For example:

[radius_client]
host=1.2.3.4
host_2=1.2.3.5
secret=radiusclientsecret

In addition, make sure that the RADIUS server is configured to accept authentication requests from the Authentication Proxy.

For advanced RADIUS configuration, see the full Authentication Proxy documentation.

Configure the Proxy for Your CyberArk Privileged Account Security Solution

Next, we'll set up the Authentication Proxy to work with your CyberArk Privileged Account Security Solution. Create a [radius_server_auto] section and add the properties listed below. If you've already set up the Duo Authentication Proxy for a different RADIUS Auto application, append a number to the section header to make it unique, like [radius_server_auto2].

Required

Optional

A completed config file that uses Active Directory should look something like:

[ad_client]
host=1.2.3.4
service_account_username=duoservice
service_account_password=password1
search_dn=cn=Users,dc=example,dc=com
 
[radius_server_auto]
ikey=DIXXXXXXXXXXXXXXXXXX
skey=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
api_host=api-XXXXXXXX.duosecurity.com
radius_ip_1=5.6.7.8
radius_secret_1=radiussecret1
client=ad_client
port=1812
failmode=safe

Make sure to save your configuration file in your text editor — or validate and save in the Proxy Manager for Windows — when you're finished making changes.

Start the Proxy

net start DuoAuthProxy

authproxyctl start

net stop DuoAuthProxy & net start DuoAuthProxy

authproxyctl restart

# /opt/duoauthproxy/bin/authproxyctl start

# /opt/duoauthproxy/bin/authproxyctl status

# /opt/duoauthproxy/bin/authproxyctl restart

If you modify your authproxy.cfg configuration after initial setup, you'll need to stop and restart the Duo Authentication Proxy service or process for your change to take effect.

You can view information about your Authentication Proxy in the Authentication Proxy Dashboard.

Configure CyberArk Privileged Account Security

Define the Duo RADIUS Authentication Method

1. Log on to your Vault server and open an command prompt window. The command utilities for configuring RADIUS are in the Vault installation folder, typically the C:\Program Files (x86)\PrivateArk\Server directory. Your Vault install directory may differ.

2. (Optional) Obtain a Vault certificate and private key from a Certificate Authority and install on your Vault machine if one is not already present. CyberArk recommends not using a self-signed certificate for RADIUS authentication.

   If you do not already have a Vault certificate and private key, use the CACert.exe utility to generate the request.

   This example command creates a certificate request file called VaultCert.req for the Vault's DNS hostname vault.acme.local with the Vault's IP address 10.1.10.110 as the subject alternate name and additional identifying information about the organization requesting the certificate:

   CACert request /reqoutfile c:\temp\VaultCert.req /country "US" /locality "Ann Arbor" /org "Acme Corp" /orgunit "IT" /commonname "vault.acme.local" /subjalt "IP:10.1.10.110"

   Submit this request to your Certificate Authority to obtain a certificate for the Vault server. Once you have the certificate, copy it to your Vault server and install it in the Vault with the CACert utility. In this example command, the new certificate name is cyberarkvault.cer:

   CACert install /CertFileName c:\temp\cyberarkvault.cer

   To see the full requirements for Vault certificates and a detailed description of this step see "Configuring RADIUS Authentication" Step 1 in the "CyberArk Privileged Account Security Installation Guide". For more information about the CACert command and its options refer to Appendix B of the "Privileged Account Security Installation Guide".

3. On the Vault server, launch the PrivateArk Server application. Use Server Central Administration to stop the Vault.

4. Create an encrypted file containing the same RADIUS secret specified in your Duo authproxy.cfg with the CAVaultManager command. This example outputs the secret radiussecret1 to the file radiusauth.dat.

   CAVaultManager SecureSecretFiles /SecretType Radius /Secret radiussecret1 /SecuredFileName radiusauth.dat
   
    ITADB399I Using encryption algorithms: Advanced Encryption Standard (AES), 256 bit,
    RSA (2048 bit), SHA2-512 (Protocol Integrity), SHA2-512 (Files Integrity).
    CAVLT044I RADIUS secret was secured successfully.

5. Make a backup copy of the DBParm.ini file in your Vault Server installation directory, and then open it in a text editor.

6. Add a new RadiusServersInfo line that specifies, in order, the IP address of your Duo Authentication Proxy server, the port specified in your [radius_server_auto] section of the authproxy.cfg file, the hostname of your Vault server, and the name of the encrypted RADIUS secret file created with the CAVaultManager command in step 4.

   RadiusServersInfo=10.1.10.101;1812;vault.acme.local;radiusauth.dat

7. Return to the PrivateArk Server Server Central Administration window to restart the Vault server.

See "Configuring RADIUS Authentication" steps 2 through 5 in the "CyberArk Privileged Account Security Installation Guide" for additional details and options.

Configure User Accounts for RADIUS

Update the authentication method for any users who you want to log in with Duo.

1. Launch the PrivateArk Client application. Double-click the Server Vault to logon as the predefined Administrator user.

2. Go to Tools → Administrative Tools → Users and Groups.

3. Click on the user you want to switch to Duo RADIUS authentication, then click the Update button to show the user's properties.

4. Click the Authentication tab and select RADIUS Authentication from the Authentication method drop-down list. Click OK.

   

5. Log off the Vault.

Configure Password Vault Web Access

1. Log on to Password Vault Web Access via your browser as the predefined Administrator user. This is typically accessed at https://yourvaultserver/PasswordVault.

2. Click on ADMINISTRATION at the top to navigate to the "System Configuration" page. Then, click on Options in the "Component Settings" table.

3. Scroll down the listed configuration items on the left to Authentication Methods. Expand this to show a list of configuration methods and click on radius.

4. In the Properties table, enter a descriptive DisplayName, like "Duo RADIUS", and set Enabled to Yes.

5. Click Apply in the lower right, and then click OK.

   

For additional information about adding Duo RADIUS authentication to please refer to the "CyberArk PVWA Integration with Duo - Implementation Guide" published by CyberArk, as well as the "RADIUS Authentication" section in the "CyberArk Privileged Account Security Installation Guide".

Test Your Setup

Navigate to the Privileged Account Security web login page and click the new Duo RADIUS option (this name matches the "DisplayName" you specified when configuring the RADIUS authentication method).

Enter your Active Directory username and password. When you enter your username and password, you will receive an automatic push or phone callback. Alternatively you can add a comma (",") to the end of your password, followed by a Duo passcode.

For example, given a username 'bob', with password 'password123' and a Duo passcode '123456', you would enter:

username: bob
password: password123,123456

In addition, you may also enter the name of an out-of-band factor in lieu of a passcode. You may choose from the following factor names:

Returning to the previous example, if you wanted to use Duo Push (rather than a passcode) to authenticate, you would enter:

username: bob
password: password123,push

You can also specify a number after the factor name if you have more than one device enrolled. So you can enter phone2 or push2 if you have two phones enrolled and you want the Duo Push or phone call request to go to your second phone instead.

Troubleshooting

Need some help? Review troubleshooting tips for the Authentication Proxy and try the connectivity tool included with Duo Authentication Proxy 2.9.0 and later to discover and troubleshoot general connectivity issues.

Also take a look at our CyberArk Knowledge Base articles or Community discussions. For further assistance, contact Support.

Next Steps

To further secure access to the CyberArk Privileged Account Security Solution, you can disable alternate authentication methods. See the "Authenticating to the Privileged Account Security Solution" section in the "CyberArk Privileged Account Security Installation Guide" for guidance.

Network Diagram

1. Primary authentication initiated to CyberArk Privileged Account Security
2. CyberArk Privileged Account Security sends authentication request to Duo Security’s authentication proxy
3. Primary authentication using Active Directory or RADIUS
4. Duo authentication proxy connection established to Duo Security over TCP port 443
5. Secondary authentication via Duo Security’s service
6. Duo Authentication Proxy receives authentication response
7. CyberArk Privileged Account Security access granted