Duo Single Sign-On for Tenable

Overview

As business applications move from on-premises to cloud hosted solutions, users experience password fatigue due to disparate logons for different applications. Single sign-on (SSO) technologies seek to unify identities across systems and reduce the number of different credentials a user has to remember or input to gain access to resources.

While SSO is convenient for users, it presents new security challenges. If a user's primary password is compromised, attackers may be able to gain access to multiple resources. In addition, as sensitive information makes its way to cloud-hosted services it is even more important to secure access by implementing two-factor authentication and zero-trust policies.

About Duo Single Sign-On

Duo Single Sign-On is our cloud-hosted SSO product which layers Duo's strong authentication and flexible policy engine on top of Tenable logins. Duo Single Sign-On acts as an identity provider (IdP), authenticating your users using existing on-premises Active Directory (AD) or another SSO IdP. Duo SSO prompts users for two-factor authentication and performs endpoint assessment and verification before permitting access to Tenable.

Duo Single Sign-On is available in Duo Premier, Duo Advantage, and Duo Essentials plans, which also include the ability to define policies that enforce unique controls for each individual SSO application. For example, you can require that Salesforce users complete two-factor authentication at every login, but only once every seven days when accessing Tenable. Duo checks the user, device, and network against an application's policy before allowing access to the application.

Configure Single Sign-On

Before configuring Tenable with Duo SSO using Security Assertion Markup Language (SAML) 2.0 authentication you'll first need to enable Duo Single Sign-On for your Duo account and configure a working authentication source.

Once you have your SSO authentication source working, continue to the next step of creating the Tenable application in Duo.

Create the Tenable Application in Duo

1. Log on to the Duo Admin Panel and navigate to Applications → Protect an Application.

2. Locate the entry for Tenable with a protection type of "2FA with SSO hosted by Duo (Single Sign-On)" in the applications list. Click Protect to the far-right to start configuring Tenable. See Protecting Applications for more information about protecting applications in Duo and additional application options. You'll need the information on the Tenable page under Downloads later.

3. Tenable uses the Mail attribute when authenticating. We've mapped the <Email Address> bridge attribute to Duo Single Sign-On supported authentication source attributes as follows:

   Bridge Attribute	Active Directory	SAML IdP
   <Email Address>	mail	Email

   If you are using a non-standard email attribute for your authentication source, check the Custom attributes box and enter the name of the attribute you wish to use instead.

4. You can adjust additional settings for your new SAML application at this time — like changing the application's name from the default value, enabling self-service, or assigning a group policy.

5. Keep the Duo Admin Panel tab open. You will come back to it later.

Duo Universal Prompt

The Duo Universal Prompt provides a simplified and accessible Duo login experience for web-based applications, offering a redesigned visual interface with security and usability enhancements.

Universal Prompt	Traditional Prompt

We've already updated the Duo Tenable application hosted in Duo's service to support the Universal Prompt, so there's no action required on your part to update the application itself. If you created your Tenable application before March 2024, you can activate the Universal Prompt experience for users from the Duo Admin Panel. Tenable applications created after March 2024 have the Universal Prompt activated by default.

If you created your Tenable application before March 2024, it's a good idea to read the Universal Prompt Update Guide for more information, about the update process and the new login experience for users, before you activate the Universal Prompt for your application.

Activate Universal Prompt

Activation of the Universal Prompt is a per-application change. Activating it for one application does not change the login experience for your other Duo applications.

The "Universal Prompt" area of the application details page shows that this application is "Ready to activate", with these activation control options:

• Show traditional prompt: Your users experience Duo's traditional prompt via redirect when logging in to this application.
• Show new Universal Prompt: (Default) Your users experience the Universal Prompt via redirect when logging in to this application.

The application's Universal Prompt status shows "Activation complete" here and on the Universal Prompt Update Progress report.

Should you ever want to roll back to the traditional prompt, you can return to this setting and change it back to Show traditional prompt. However, this will still deliver the Duo prompt via redirect, not in an iframe. Keep in mind that support for the traditional Duo prompt ended for the majority of applications in March 2024.

Universal Update Progress

Click the See Update Progress link to view the Universal Prompt Update Progress report. This report shows the update availability and migration progress for all your Duo applications. You can also activate the new prompt experience for multiple supported applications from the report page instead of visiting the individual details pages for each application.

Enable Tenable for SSO

1. Log into your Tenable account as an administrative user.

2. Click the menu icon in the top left corner of the page.

3. In the left menu sidebar, scroll down and click Settings. The "Settings" page opens.

4. Under "Account Management", click SAML. The "SAML" page opens.

5. Click Create.

6. Under "SAML Settings", click the drop-down menu and select Import XML.

7. Click the TYPE drop-down menu and select SAML 2.0.

8. Return to the Duo Admin Panel. Under "Downloads", click Download XML.

9. Return to your Tenable "SAML" page. Under "IMPORT", click Add File. Open the XML file you downloaded from Duo earlier.

10. At the bottom of the page, click Save. The "SAML" page opens.

11. Click the UUID you created. Make sure the Enabled toggle switch is ON.

12. Scroll to the bottom of the page and click the User Auto Provisioning Enabled toggle switch.

13. Click the IdP Assigns User Role at Provisioning toggle switch.

14. Click the IdP Resets User Role at Each Login toggle switch.

15. At the bottom of the page, click Save.

16. Locate the UUID you created. On your UUID row, in the "ACTIONS" column, click the menu icon and then click Download SAML SP metadata.

17. Return to the Duo Admin Panel. Under "Service Provider", click Choose File. Open the XML file you downloaded from Tenable earlier.

18. In the Duo Admin Panel, scroll to the bottom of the page and click Save.

Group Mapping

You have the option to map Duo groups to different roles in Tenable. To map Duo groups, do the following.

1. Log into your Tenable account as an administrative user.

2. Click the menu icon in the top left corner of the page.

3. In the left menu sidebar, scroll down and click Settings. The "Settings" page opens.

4. Under "Account Management", click Access Control. The "Access Control" page opens.

5. Click the Roles tab.

6. You can map an existing role or map a new role to Duo. To map a new role, click Add Role and follow the on-screen instructions.

7. Click the checkbox next to the role you want to map.

8. Click Export. The "Export" window opens.

9. Under "FORMATS", click CSV and then click Export.

10. Open the CSV file you downloaded earlier. In row 2, column D of the CSV file, copy the UUID and paste it into the Duo Admin Panel Tenable Roles field.

11. In the Duo Admin Panel, select the applicable Duo group from the Duo groups drop-down menu.

    

12. Scroll to the bottom of the page and click Save.

Learn more about Tenable SSO at Tenable Documentation.

Using SSO

You can log on to Tenable using your ACS URL e.g., https://cloud.tenable.com/saml/login/your-unique-placeholder. You will be automatically redirected to Duo Single Sign-On to begin authentication.

Active Directory Login

With Active Directory as the Duo SSO authentication source, enter the primary username (email address) on the Duo SSO login page and click or tap Next.

Enter the AD primary password and click or tap Log in to continue.

Enable Duo Passwordless to log in to Duo SSO backed by Active Directory authentication without entering a password in the future.

SAML Login

With another SAML identity provider as the Duo SSO authentication source, Duo SSO immediately redirects the login attempt to that SAML IdP for primary authentication. Users do not see the Duo SSO primary login screen.

Duo Authentication

Successful verification of your primary credentials by Active Directory or a SAML IdP redirects back to Duo. Complete Duo two-factor authentication when prompted and then you'll return to Tenable to complete the login process.

* Universal Prompt experience shown.

You can also log into Tenable using Duo Central, our cloud-hosted portal which allows users to access all of their applications in one spot. Link to Tenable in Duo Central by adding it as an application tile. Once the tile has been added, log into Duo Central and click the tile for IdP-initiated authentication to Tenable.

Congratulations! Your Tenable users now authenticate using Duo Single Sign-On.

See the full user login experience, including expired password reset (available for Active Directory authentication sources) in the Duo End User Guide for SSO.

Enable Remembered Devices

To minimize additional Duo two-factor prompts when switching between Tenable and your other Duo Single Sign-On SAML applications, be sure to apply a shared "Remembered Devices" policy to your SAML applications.

Troubleshooting

Need some help? Try searching our Knowledge Base articles or Community discussions. For further assistance, contact Support.