In today’s interconnected enterprise landscapes, secure communication between SAP systems and external applications is critical to safeguard sensitive data and prevent cyber threats. Remote Function Calls (RFCs) and HTTPS protocols are commonly used communication methods within SAP environments, facilitating data exchange and remote procedure execution. However, if not properly secured, these channels can expose organizations to risks such as unauthorized access, data interception, and manipulation. This article delves into best practices and security mechanisms for protecting communication using RFCs and HTTPS in SAP.
¶ Understanding RFCs and HTTPS in SAP
RFC is SAP’s proprietary protocol for invoking functions in a remote system, enabling seamless integration between SAP systems or between SAP and non-SAP systems. RFCs come in various types, including synchronous, asynchronous, transactional, and queued RFCs, each serving different use cases.
HTTPS (HTTP Secure) is the secure version of HTTP, using SSL/TLS encryption to protect data exchanged over the web. SAP systems use HTTPS to secure web services, SAP Fiori applications, and other web-based communications.
- Eavesdropping: Unauthorized interception of sensitive data in transit.
- Man-in-the-Middle (MitM) Attacks: Attackers intercept and potentially alter data between communicating systems.
- Unauthorized Access: Improper authentication allows attackers to execute unauthorized actions.
- Data Tampering: Malicious modification of messages during transmission.
SNC provides end-to-end encryption and authentication for RFC connections using standard security protocols like Kerberos, X.509 certificates, or third-party security products.
- Implement SNC to encrypt RFC traffic and prevent eavesdropping.
- Configure SNC wallets and certificates properly on both client and server systems.
- Use SAP user accounts with strong passwords and proper authorization profiles.
- Avoid using background or system users with broad privileges for RFC connections.
- Enable Single Sign-On (SSO) via SNC or SAML tokens to enhance security.
- Limit RFC connections to trusted systems only by defining explicit destinations in transaction SM59.
- Regularly audit and remove unused or obsolete RFC destinations.
¶ 4. Implement Message Integrity and Replay Protection
- Use SNC’s capabilities to verify message integrity and prevent replay attacks.
- Consider using digital signatures for critical RFC calls.
- Always configure SAP Web Dispatcher, SAP Gateway, and web servers to use strong SSL/TLS protocols.
- Disable outdated protocols like SSL 2.0, SSL 3.0, and weak cipher suites.
¶ 2. Use Valid and Trusted Certificates
- Obtain certificates from trusted Certificate Authorities (CAs).
- Regularly renew and update certificates before expiration.
- Implement certificate pinning if supported.
¶ 3. Enforce Authentication and Authorization
- Use SAP’s authentication mechanisms such as SAP Logon Tickets, SAML, or OAuth for HTTPS access.
- Protect SAP Fiori launchpad and web services with robust role-based access controls.
¶ 4. Implement Secure Cookies and HTTP Headers
- Use secure cookie attributes (Secure, HttpOnly, SameSite) to protect session cookies.
- Configure HTTP headers like Content Security Policy (CSP), X-Frame-Options, and Strict-Transport-Security (HSTS) to mitigate attacks like clickjacking and protocol downgrade.
¶ Monitoring and Incident Response
- Monitor RFC and HTTPS traffic logs for suspicious activities.
- Use SAP Solution Manager or third-party security tools to detect anomalies.
- Define incident response procedures for communication breaches.
Securing communication channels such as RFC and HTTPS is fundamental to protecting SAP landscapes from cyber threats. By implementing encryption, strong authentication, authorization controls, and adhering to SAP’s security best practices, organizations can ensure confidentiality, integrity, and availability of inter-system communications. Continuous monitoring and proactive management are essential to maintaining a robust security posture in complex SAP environments.