Azure SQL Database Security Reference

This document provides a comprehensive reference for security features and configurations available for Azure SQL Database. Understanding and implementing these security measures is crucial for protecting your data.

Overview of Azure SQL Database Security

Azure SQL Database offers a robust set of security features designed to protect your data at rest and in transit. These features include network security, authentication, authorization, threat detection, and data masking.

Key Security Pillars

• Network Security: Control access to your database through firewalls, virtual networks, and private endpoints.
• Authentication: Verify the identity of users and applications accessing your database. Supports SQL authentication and Azure Active Directory authentication.
• Authorization: Grant specific permissions to users and roles, ensuring the principle of least privilege.
• Data Protection: Encrypt data at rest (Transparent Data Encryption - TDE) and in transit (SSL/TLS).
• Threat Detection & Auditing: Monitor for suspicious activities and audit database events for compliance and security analysis.
• Data Masking: Obfuscate sensitive data for non-privileged users.

Network Security

Firewall Rules

Configure server-level and database-level firewall rules to restrict access based on IP addresses. This is the primary mechanism to control network access.

-- Example: Creating a server-level firewall rule
USE master;
CREATE LOGIN MyUser WITH PASSWORD = 'Str0ngPa$$w0rd';
GO

-- Example: Granting access to a specific IP address range
EXEC sp_set_firewall_rule N'AllowMyIP', 'YOUR_IP_ADDRESS', 'YOUR_IP_ADDRESS';
GO

Virtual Network Service Endpoints

Secure your Azure SQL Database by associating it with your Azure Virtual Network (VNet). This restricts access to resources within that VNet.

Private Endpoint

Use Azure Private Link to access Azure SQL Database over a private endpoint, ensuring traffic stays within the Azure backbone network.

Authentication and Authorization

SQL Authentication

Traditional username and password-based authentication. Use strong passwords and manage logins carefully.

Azure Active Directory (Azure AD) Authentication

Integrate with Azure AD for centralized identity management, single sign-on, and multi-factor authentication (MFA).

Supported Azure AD Authentication Methods:

• Azure AD Password Authentication
• Azure AD Integrated Authentication
• Azure AD Multi-Factor Authentication
• Managed Identities for Azure resources

Role-Based Access Control (RBAC)

Leverage built-in database roles (e.g., db_owner, db_datareader) and create custom roles for fine-grained permission management.

Data Protection

Transparent Data Encryption (TDE)

TDE encrypts data files and log files at rest. It is enabled by default for new Azure SQL Databases.

Always Encrypted

Always Encrypted allows sensitive data to be encrypted within client applications and never be revealed to the database engine. This is suitable for highly sensitive data.

SSL/TLS Encryption

All connections to Azure SQL Database are encrypted using SSL/TLS by default. Ensure your applications are configured to enforce SSL.

Threat Detection and Auditing

Azure SQL Auditing

Auditing tracks database events and writes them to an audit log in Azure Blob Storage, Azure Log Analytics, or Azure Event Hubs. This is essential for compliance and security analysis.

Advanced Threat Protection (ATP)

ATP provides a layer of security intelligence that detects anomalous activities, potential SQL injection, brute force attacks, and other threats.

Data Masking

Dynamic Data Masking

Dynamic data masking limits sensitive data exposure by masking it to non-privileged users. You can define masking rules for specific columns.

-- Example: Masking an email column
ALTER TABLE dbo.Customers
ALTER COLUMN Email ADD MASKED WITH (FUNCTION = 'email()');
GO

Best Practices

• Implement the principle of least privilege for all users and applications.
• Use Azure AD authentication with MFA whenever possible.
• Configure firewall rules to restrict access to only necessary IP addresses or VNets.
• Enable TDE and SSL/TLS for data protection.
• Regularly review audit logs and investigate security alerts from ATP.
• Use dynamic data masking for sensitive columns accessed by less privileged users.
• Keep your database software up-to-date and apply security patches.