Security in SQL Server Analysis Services

Updated: 2023-10-27 Article ID: 897987

Securing your SQL Server Analysis Services (SSAS) solution is crucial for protecting sensitive data and ensuring that users have appropriate access to information. SSAS provides a robust set of security features that can be implemented at various levels.

Authentication and Authorization

Analysis Services uses Windows authentication by default. Users are authenticated against the Windows domain or local machine. Authorization is then managed through SSAS roles.

Windows Authentication

When connecting to an SSAS instance, the client application (e.g., SQL Server Management Studio, Power BI) passes the user's Windows credentials. Analysis Services verifies these credentials against the identity provider.

Server Roles

The SSAS server itself has built-in roles that control administrative access to the server instance. These roles are typically managed in SQL Server Management Studio (SSMS).

  • Sysadmin: Full control over the SSAS server instance.
  • ServerAdmin: Can perform administrative tasks but cannot manage server-level security.

Database Roles and Permissions

Within each Analysis Services database (cube, dimension, etc.), you define roles to grant specific permissions to users and groups.

Creating and Managing Roles

Roles are created and managed using tools like SSMS or Visual Studio with Analysis Services projects.

  1. Connect to the SSAS instance in SSMS.
  2. Navigate to the specific Analysis Services database.
  3. Right-click on "Roles" and select "New Role".
  4. Define the role name, members (users or Windows groups), and grant database permissions.

Database Permissions

Permissions can be assigned to roles at the database level:

  • Read Definition: Allows viewing of objects (cubes, dimensions, etc.) but not data.
  • Read Data: Allows querying of data within the database.
  • Read All: Allows reading both definitions and data.
  • Full Control: Full administrative control over the database.

Cube and Object-Level Security

For more granular control, you can implement security at the cube or even row/cell level.

Cube Permissions

You can grant or deny permissions to specific cubes within a database role. This allows users in a role to access some cubes but not others.

Row-Level Security

Row-level security in SSAS typically involves using security roles with MDX or DAX expressions to filter data based on the logged-in user. This ensures users only see data relevant to their department, region, or other criteria.

-- Example MDX expression for row-level security
IIF(
    USER_PRINCIPAL_NAME() = 'DOMAIN\UserA',
    '[Geography].[City].&[London]',
    '[Geography].[City].&[Paris]'
)

Cell-Level Security

Cell-level security restricts access to specific data cells within a cube. This is often used for sensitive financial data or performance metrics.

Best Practices

  • Principle of Least Privilege: Grant only the necessary permissions to users and roles.
  • Use Windows Groups: Manage permissions by assigning users to Windows security groups and then assigning those groups to SSAS roles.
  • Regular Auditing: Periodically review role memberships and permissions to ensure they are still appropriate.
  • Document Security Policies: Maintain clear documentation of your security design and implementation.
  • Separate Roles for Administration and Data Access: Ensure that administrative roles are distinct from roles that grant access to data.

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