Duo Single Sign-On for Cloudflare Access

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 Cloudflare Access 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 Cloudflare Access.

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 Cloudflare Access. Duo checks the user, device, and network against an application's policy before allowing access to the application.

Configure Single Sign-On

Before configuring Cloudflare Access 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 Cloudflare Access application in Duo.

Create the Cloudflare Access Application in Duo

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

2. Locate the entry for Cloudflare Access 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 Cloudflare Access. See Protecting Applications for more information about protecting applications in Duo and additional application options. You'll need the information on the Cloudflare Access page under Downloads later.

3. Cloudflare Access 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 Cloudflare Access 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 Cloudflare Access application before March 2024, you can activate the Universal Prompt experience for users from the Duo Admin Panel. Cloudflare Access applications created after March 2024 have the Universal Prompt activated by default.

If you created your Cloudflare Access 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 Cloudflare Access for SSO

1. Log into your Cloudflare Access account as an administrative user. The "Accounts" page opens.

2. Click your account.

3. In the left menu sidebar, click Zero Trust.

4. In the left menu sidebar, click Settings. The "Settings" page opens.

5. Click Authentication. The "Authentication" page opens.

6. Under "Login methods", click Add new and then click SAML. The "Add SAML" page opens.

7. Enter a unique name for your identity provider in the Name field. Copy the name you entered and paste it into the Duo Admin Panel Team name field under "Service Provider".

   

8. In the Duo Admin Panel, click Download XML under "Downloads".

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

10. Return to your Cloudflare Access account page and click the file upload box, as shown in the image below. Open the XML file you downloaded from Duo earlier.

    

11. Scroll down to "Optional configurations" and click the Sign SAML authentication request toggle switch.

12. Scroll to the bottom of the page and click Save. You are returned to the "Authentication" page.

13. Under "Login methods", click Test next to the identity provider you created earlier.

14. A new web page opens and redirects you to Duo Single Sign-On for authentication.

15. Once the test passes, close the web page.

Add an Application

You can add applications to be used with Cloudflare Access. To add an application, do the following:

1. Log into your Cloudflare Access account as an administrative user. The "Accounts" page opens.

2. Click your account.

3. In the left menu sidebar, click Zero Trust.

4. In the left menu sidebar, click Access and then click Applications.

5. Click Add an application.

6. Select the type of application you want to add and follow the on-screen instructions.

7. After you have configured your application, click Add application. In the image below, an example bookmark application was added.

   

App Launcher Rules

You can define rules for users who access the App Launcher. To define rules for users, do the following:

1. Log into your Cloudflare Access account as an administrative user. The "Accounts" page opens.

2. Click your account.

3. In the left menu sidebar, click Zero Trust.

4. In the left menu sidebar, click Settings. The "Settings" page opens.

5. Click Authentication. The "Authentication" page opens.

6. Under "App Launcher", click Manage.

7. Click the Rules tab and then click Add a rule.

8. Enter a name for your rule into the Rule name field.

9. Select an action from the Rule action drop-down menu.

10. Finish configuring your rule as required and then click Save.

    

11. Click the Authentication tab and then click the Accept all available identity providers toggle switch.

12. Under "Session duration", select the desired session time and then click Save.

Learn more about Cloudflare Access SSO at Cloudflare Docs.

Using SSO

You can log on to Cloudflare Access by navigating to your Cloudflare Access SSO page e.g., https://example-sso.cloudflareaccess.com/. Click Login and then click SAML - example-sso to be 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 Cloudflare Access to complete the login process.

* Universal Prompt experience shown.

Cloudflare Access supports SP-initiated authentication only, meaning that you must start your SSO login from that application's sign-in page. You won't be able to add Cloudflare Access as an application tile in Duo Central for IdP-initiated logins.

Congratulations! Your Cloudflare Access 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 Cloudflare Access 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.