Authentication in SQL Server Analysis Services

Authentication is the process of verifying the identity of a user or application that is attempting to connect to SQL Server Analysis Services (SSAS). SSAS supports two primary authentication modes: Windows Authentication and SQL Server Authentication.

Authentication Modes

Windows Authentication

Windows Authentication is the default and recommended method for authenticating users connecting to SSAS. It leverages the Windows security infrastructure to verify user credentials. When a client application connects to SSAS using Windows Authentication, the SSAS server verifies the user's identity against the Windows domain or local machine.

• Integrated Security: Clients connect using their current Windows login credentials.
• Service Principal Names (SPNs): Properly configured SPNs are crucial for Kerberos authentication, which is often used with Windows Authentication in domain environments to provide single sign-on capabilities and enhanced security.
• SSPI Packages: SSAS uses the Security Support Provider Interface (SSPI) to handle authentication, supporting protocols like Kerberos and NTLM.

SQL Server Authentication

SQL Server Authentication uses logins and passwords created and managed directly within SQL Server. This mode is useful when connecting from applications or services that do not have direct Windows credentials, or when you want to manage access independently of Windows user accounts. When using SQL Server Authentication, SSAS relies on the underlying SQL Server instance for credential validation.

• Login and Password: Users provide a specific SSAS login name and password.
• Database Engine Integration: SSAS authentication relies on the SQL Server Database Engine for validating SQL Server logins.
• Security Considerations: Ensure strong passwords and secure transmission of credentials if using SQL Server Authentication.

Connecting with Authentication

When establishing a connection to SSAS, the client application or tool needs to specify the authentication method and provide the necessary credentials. This is typically configured in the connection string or dialog boxes within tools like SQL Server Management Studio (SSMS) or client applications built using Analysis Services client libraries.

Connection String Examples

Windows Authentication

Provider=MSOLAP.8;Data Source=YourServerName;Initial Catalog=YourDatabaseName;Integrated Security=SSPI;Impersonation Level=Impersonate;

SQL Server Authentication

Provider=MSOLAP.8;Data Source=YourServerName;Initial Catalog=YourDatabaseName;User ID=YourSSASLogin;Password=YourPassword;Persist Security Info=True;

Best Practices

• Prefer Windows Authentication for internal users and applications running within the Windows domain for enhanced security and ease of management.
• When using SQL Server Authentication, enforce strong password policies and consider using dedicated SSAS logins rather than shared credentials.
• Ensure that the service account running the Analysis Services instance has appropriate permissions and is configured securely.
• Implement secure communication channels (e.g., SSL/TLS) if credentials or sensitive data are transmitted over untrusted networks.

Authentication and Authorization

Authentication is the first step in securing your SSAS data. Once a user's identity is verified, Authorization determines what that user is allowed to do and what data they can access. SSAS uses Windows groups, SSAS roles, and database permissions to manage authorization.