Security Deployment in SQL Server Analysis Services
This document provides comprehensive guidance on deploying and managing security for SQL Server Analysis Services (SSAS) instances. Effective security configuration is crucial for protecting your multidimensional and tabular models, ensuring data integrity, and controlling user access.
Understanding the SSAS Security Model
SSAS employs a role-based security model. Security is primarily managed through:
- Server Roles: Control administrative access to the SSAS server instance itself.
- Database Roles: Grant permissions to users or groups for specific SSAS databases.
- Object-Level Security: Restrict access to specific cubes, dimensions, measures, and other objects within a database.
- Cell-Level Security: Provide granular control over individual data cells based on user roles and conditions.
Configuring Server Roles
Server roles are managed directly within SQL Server Management Studio (SSMS) by connecting to the SSAS instance. The primary server roles include:
- Administrator: Full control over the SSAS server, including managing databases and security settings.
- Server Data Source Access: Permissions to access data sources used by SSAS.
- Database Creator: Ability to create new SSAS databases.
To configure server roles, navigate to the SSAS instance in SSMS, right-click on the instance name, select 'Properties', and then go to the 'Security' page.
Configuring Database Roles
Database roles define permissions at the SSAS database level. Common database roles include:
- DBAdmin: Full control over a specific SSAS database.
- DBReader: Read access to the database.
- DBDataMiner: Permissions to mine data within the database.
- DBBuiltinAdministrator: (Legacy role, use DBAdmin)
In SSMS, expand the SSAS instance, then expand 'Databases'. Right-click on the desired database, select 'New Role', and configure membership and permissions.
Implementing Object-Level Security
Object-level security (OLS) allows you to restrict access to specific cubes, dimensions, measure groups, perspectives, or tables within a tabular model. This is configured within the SSAS project in Visual Studio or by directly modifying the SSAS database using MDX or DAX scripts.
For Multidimensional Models:
- Open your SSAS project in Visual Studio.
- In Solution Explorer, right-click on 'Roles' and select 'New Role'.
- On the 'General' page, select 'Database role'.
- On the 'General' page, select 'Object access'.
- For each object (cube, dimension, etc.), choose 'Read' or 'Deny' access.
For Tabular Models:
- In Visual Studio, right-click on 'Roles' and select 'New Role'.
- Configure the 'Table Permissions' and 'Column Permissions' for the role.
Configuring Cell-Level Security
Cell-level security (CLS) restricts access to specific data cells within a cube based on user roles. This is typically implemented using MDX expressions within the role definition.
In SSMS, when editing a role, you can define CLS rules on the 'Cell Data' page. You specify which cells are restricted and for which users or roles.
Tip: Carefully plan your CLS requirements. Complex CLS rules can impact query performance. Consider using perspectives or pre-aggregated data for common user views.
Deployment Considerations
When deploying SSAS solutions, ensure that security configurations are accurately transferred. This can involve:
- Scripting Security: Scripting role definitions and permissions using SSMS or PowerShell can be part of your deployment automation.
- Permissions Management: Ensure that the accounts used for deployment have the necessary permissions on the target SSAS server.
- Integration with Active Directory: Leverage Active Directory groups for managing role memberships to simplify administration.
- Auditing: Implement auditing to track security-related events, such as role modifications or access attempts.
Security Best Practices
- Principle of Least Privilege: Grant users and roles only the minimum permissions necessary to perform their tasks.
- Regular Audits: Periodically review and audit role memberships and permissions.
- Use Windows Groups: Assign Windows security groups to SSAS roles instead of individual users for easier management.
- Secure Data Sources: Ensure that the credentials used by SSAS to connect to data sources are secure and have appropriate permissions.
- Test Thoroughly: After implementing security settings, rigorously test them from the perspective of different user roles.
- Document Security: Maintain clear documentation of your SSAS security model, including role definitions and their associated permissions.
Important: Never grant unnecessary administrative privileges. Regularly update SSAS and related Windows components to patch any security vulnerabilities.