Securing SQL Server

New: 12 December 2006

Securing SQL Server involves three areas: the platform and network, principals and securables, and applications that access the database. The following topics will guide you through creating and implementing an effective security plan.

You can find more information on SQL Server security at the SQL Server Web site, including a best practice guide and a security checklist. This site also contains the latest service pack information and downloads.

Platform and Network Security

The platform for SQL Server includes the physical hardware and networking systems connecting clients to the database servers, as well as the binary files used to process database requests.

Physical Security

Best practices for physical security strictly limit access to the physical server and hardware components. For example, use locked rooms with restricted access for the database server hardware and networking devices. In addition, limit access to backup media by storing it at a secure offsite location.

Implementing physical network security begins with keeping unauthorized users off the network. The following chart contains more information on networking security information.

Operating System Security

Operating system service packs and upgrades include important security enhancements. Apply all patches and upgrades to the operating system after testing them with your database applications.

Firewalls also provide effective ways to implement security. Logically, a firewall is a separator or restrictor of network traffic, which can be configured to enforce your organization's data security policy. Using a firewall increases security at the operating system level by providing a chokepoint where your security measures can be focused. The following table contains more information on using a firewall with SQL Server.

Surface area reduction is a security measure that involves stopping or disabling unused components. Surface area reduction helps to improve security by providing fewer avenues for potential attacks on a system. The key to limiting the surface area of SQL Server includes running required services with "least privilege" by only granting services and users the appropriate rights. The following chart contains more information on services and system access.

If your SQL Server system uses Internet Information Services (IIS), additional steps are required to secure the surface of the platform. The following chart contains information on SQL Server and Internet Information Services.

SQL Server Operating System Files Security

SQL Server uses operating system files for operation and data storage. Best practices for file security requires that you restrict access to these files. The following chart contains information on these files.

SQL Server service packs and upgrades provide enhanced security. To determine the latest available service pack available for SQL Server, see the SQL Server Web site.

You can use the following script to determine the service pack installed on your system:

SELECT CONVERT(char(20), SERVERPROPERTY('productlevel'));
GO

Principals and Database Object Security

Principals are the individuals, groups, and processes granted access to SQL Server. Securables are the server, database and objects the database contains. Each has a set of permissions that can be configured to further minimize the SQL Server surface area. The following chart contains information on principals and securables.

For more information on database and application security, see Security Considerations for Databases and Database Applications.

Encryption and Certificates

Encryption does not solve access control problems. However, it enhances security by limiting data loss even in the normally rare occurrence that access controls are bypassed. For example, if the database host computer is misconfigured and a hacker obtains sensitive data, such as credit card numbers, that stolen information is useless if it is encrypted. The following chart contains more information on encryption in SQL Server.

Certificates are software "keys" shared between two servers that allow secure communications by way of strong authentication. You can create and use certificates in SQL Server to enhance object and connection security. The following chart contains information on using certificates with SQL Server.

Application Security

SQL Server security best practices include writing secure client applications. For more information on server access and SQL Server client applications, see SQL Server Programming Overview.

For more information on securing client applications at the networking layer, see Client Network Configuration.

For more information on writing applications that use native XML services, see Writing Client Applications.

SQL Server Security Tools, Utilities, Views, and Functions

SQL Server provides tools, utilities, views, and functions that can be used to configure and administer security.

SQL Server Security Tools and Utilities

The following chart contains information on SQL Server tools and utilities that you can use to configure and administer security.

SQL Server Security Catalog Views and Functions

The Database Engine exposes security information in several views and functions that are optimized for performance and utility. The following chart contains information on security views and functions.

See Also

Other Resources

Security Considerations for a SQL Server Installation

Help and Information

Getting SQL Server 2005 Assistance