Overview

This use case explains how Certificate-Based SSO is implemented in Drupal as a secure alternative to traditional client_secret authentication. Using the OAuth Client & OpenID Connect SSO module, Drupal authenticates with Identity Providers through certificate-based methods like private_key_jwt. This improves security, supports Zero Trust and compliance standards, and reduces the risk of credential exposure while maintaining a seamless user login experience.

Prerequisites:

In this section, we’ll discuss everything from requirements and implementation process to results.

• miniOrange OAuth Client module (version 8.x and above) is installed and enabled.
• Administrator access to module configuration.
• OAuth Provider is configured and reachable.

Problem

When using OAuth 2.0 or OpenID Connect (OIDC) for Drupal SSO, applications typically authenticate using a shared client_secret with the Identity Provider. Although easy to configure, storing long-lived shared secrets creates security, compliance, and operational challenges, including credential exposure risks, complex secret rotation, and difficulty aligning with Zero Trust and enterprise security standards followed by organizations using providers like Microsoft, Okta, and Ping Identity.

Who will suffer?

This issue mainly affected organizations and people in charge who work in companies or places where they have to follow a lot of rules.

• Government and Enterprise Organizations
• Organizations managing enterprise Drupal environments and operating under compliance standards like FedRAMP, ISO 27001, and Zero Trust Architecture faced security and operational challenges with traditional shared secret authentication. They required a more secure and compliant authentication approach instead of relying on long-lived static client secrets.
• Security and Identity Teams
• The teams that take care of security and manage user credentials had to deal with risks and work because they had to store and change client secrets by hand.
• Organizations Using Modern Identity Providers
• Companies that use Drupal with Identity providers like Microsoft, Okta and Ping Identity for security need a way to use certificate-based authentication, like private_key_jwt.

Solution

We implemented certificate-based Single Sign-On (SSO) authentication to make OAuth/OIDC client authentication more secure. This is an alternative to the client_secret authentication method.

Now our Drupal application uses certificate-based private_key_jwt authentication of a static shared secret. This helps us authenticate securely.

The solution helps organizations:

• Eliminate dependency on static shared secrets
• Reduce the risk of credential exposure and application impersonation
• Align with Zero Trust and enterprise security standards
• Support modern Identity Provider requirements for certificate-based authentication
• Improve secure key management and credential rotation practices
• Maintain secure authentication without affecting the end-user login experience

The implementation aligned the Drupal SSO environment with enterprise-grade authentication and compliance standards.

Result

The implementation enabled secure certificate-based authentication in Drupal using private_key_jwt instead of traditional shared secrets. It reduced dependency on long-lived client_secret values, improved compliance readiness, and simplified secure authentication with modern Identity Providers.

Conclusion

By adopting certificate-based SSO, organizations strengthened the security of their Drupal authentication flow and aligned with modern enterprise security standards such as Zero Trust and compliance frameworks. The solution provided a scalable, secure, and future-ready approach to OAuth/OIDC authentication without affecting the end-user experience.