As enterprises increasingly adopt hybrid IT landscapes—leveraging both on-premise and cloud-based SAP solutions—the need for secure, seamless user authentication across these environments becomes critical. SAP Single Sign-On (SSO) provides a robust mechanism to streamline authentication, improve user experience, and enhance security. One of its key use cases is enabling Cloud-to-On-Premise Integration without compromising identity management and access control.
This article explores how SAP SSO can be implemented to enable secure communication and authentication between cloud-based SAP applications (e.g., SAP Business Technology Platform - BTP) and on-premise SAP systems.
¶ The Challenge of Hybrid Landscapes
Hybrid environments often involve different identity providers, security protocols, and user management frameworks. Some common challenges include:
- Managing multiple credentials for users across cloud and on-premise systems.
- Securing data exchange between cloud services and internal networks.
- Enabling seamless user experiences without repeated logins.
- Ensuring compliance with corporate security policies.
SAP SSO addresses these by centralizing authentication and enabling secure identity propagation.
SAP Single Sign-On is a comprehensive solution that provides secure and seamless user access across SAP systems. It supports various authentication mechanisms such as:
- Kerberos/SPNEGO
- X.509 Certificates
- SAML 2.0
- OAuth 2.0 and OpenID Connect
For cloud-to-on-premise scenarios, SAML 2.0 and Principal Propagation are typically used.
- SAP Business Technology Platform (SAP BTP): The cloud environment where SAP applications are hosted.
- SAP Cloud Connector (SCC): A secure tunnel between SAP BTP and the on-premise network.
- Identity Provider (IdP): Usually a corporate IdP like Azure AD or SAP Identity Authentication Service (IAS).
- On-Premise SAP Systems: Backend systems like SAP S/4HANA, SAP ERP, etc.
- SAP SSO 3.0 (or higher): Installed and configured on-premise for managing authentication.
- User Login: The user accesses the SAP BTP application and logs in via the corporate IdP using SAML 2.0.
- Assertion and Token Exchange: SAP BTP receives the SAML assertion and uses it to create a short-lived security token.
- Cloud Connector Integration: SAP Cloud Connector uses this token to authenticate the user and initiate the call to the on-premise system.
- Principal Propagation: The identity (e.g., user ID) is propagated to the backend system, which uses SAP SSO to authenticate the user without requiring separate credentials.
- Seamless User Experience: Users log in once and access both cloud and on-premise applications.
- Centralized Authentication: Integrates with enterprise IdPs for single point of user management.
- Strong Security Posture: Uses industry-standard protocols like SAML 2.0 and TLS.
- Audit and Compliance: Provides traceability and audit logs of user access.
- Reduced Administrative Overhead: Minimizes password management and support issues.
- Use a Trusted IdP: Ensure your IdP supports SAML 2.0 and integrates with SAP IAS or directly with SAP BTP.
- Configure Principal Propagation Correctly: Align user IDs across cloud and on-premise systems.
- Secure the Cloud Connector: Use encrypted channels and enforce strict access controls.
- Test End-to-End Scenarios: Validate both authentication and authorization in real-world scenarios.
- Keep Systems Updated: Regularly patch SAP SSO, Cloud Connector, and identity services.
- Accessing SAP S/4HANA On-Premise from Fiori Launchpad on SAP BTP.
- Integrating SuccessFactors (cloud) with SAP ERP HCM (on-premise).
- Consuming OData services securely from on-premise systems in cloud applications.
As hybrid SAP environments become the norm, implementing SAP Single Sign-On for cloud-to-on-premise integration is not just beneficial—it’s essential. By leveraging SAML 2.0, principal propagation, and SAP Cloud Connector, businesses can ensure secure and seamless authentication across their SAP landscapes. The result is improved security, simplified user access, and a more efficient IT environment.