Introduction to SQL Server 2000 Security

Dave Watts

CTO, Fig Leaf Software

http://www.figleaf.com/

What’s this presentation about?

What kinds of security problems may occur with SQL Server?

How can you configure your SQL Server to be secure?

What do you have to do within your applications to keep SQL Server secure?

About SQL Server

Lots of functionality

Easy to use and manage, compared to other products

Originally popular as a workgroup product, but aimed at enterprise use

Not “secure by default”

Not just used on “database servers”, but often bundled with other products

Security problems

Buffer overflows – typically do not require authorization for success.

SQL injection – attacker can run arbitrary SQL commands through client application with rights of that application.

Security

Installation and initial configuration

Network connectivity

Trusted and untrusted connections

Database logins, roles, and rights

Application security

Data validation

Installation and initial configuration

Service user accounts

Filesystem ACLs

Default roles and permissions within SQL Server

Control access to system and extended stored procedures

Drop sample databases

User accounts

SQL Server and SQL Server Agent may run as SYSTEM, or as specific users.

SQL Server should run as a low-privilege local user account.

SQL Server Agent may need to be a domain account, if replication or other network functionality is being used.

User account configuration

During install, specific user accounts can be chosen.

The installer will grant those accounts the necessary rights to run SQL Server and related processes.

It will also grant filesystem and registry ACLs needed to run SQL Server.

You will need to create the accounts before installation.

SQL Server 2000 on Windows Server 2003

Requires SQL Server 2000 SP2 or higher.

During installation, you can’t choose a lower-privilege user account!

You will need to manually set ACLs and account rights yourself!

Documentation available on MS site, SQL Security site.

Network topology

SQL Server should not be exposed on the public Internet.

If possible, it should only be available to the web server(s) using it and to internal administrative workstations.

If it needs to be exposed, exposure should be limited to specific IP addresses or through VPN.

User authentication

SQL Server supports two types of connections: Windows Authentication (“trusted”) SQL Server logins (“untrusted”)

Trusted connections

Generally recommended best practice.

Windows Authentication uses existing Windows accounts.

Takes advantage of built-in Windows security functionality:

Account management Password management Auditing

Trusted connections, cont’d

Windows Authentication uses the security context of the client process.

With CF, this means the CF service account would be used for authentication.

The Windows password is not transferred between the client and server.

Untrusted connections

Native SQL Server logins do not rely on Windows security.

Most CF applications use native SQL Server logins.

Usernames and passwords are passed as slightly obfuscated text.

Untrusted connections, cont’d

SSL can be used between web server and database server to protect credentials from being sniffed.

CF and SQL Server authentication CFMX doesn’t support trusted connections with the

included JDBC driver.

The latest version of DataDirect Connect for JDBC does support trusted connections.

Using trusted connections would require that the CF Server account have rights to all databases used by a web server.

Impractical unless hosting a single application, or using multiple instances.

Network connectivity

Supported protocols TCP/IP IPX/SPX Named Pipes

TCP/IP is MS recommended choice.

By default, connections between clients and servers use plaintext!

Demonstration

Viewing database connection information for untrusted connections

Encryption options for database connections

By default, connections between clients and servers use plaintext.

TCP/IP and SSL

Multiprotocol

CF 5 vs CFMX CF 5 uses ODBC functionality CFMX uses DataDirect JDBC drivers

TCP/IP default listening ports

TCP/1433 – client connections

UDP/1434 – discovery

TCP/2433 – client connections if “hide server” option enabled.

If named instances of SQL Server are installed, each will listen on a different, user-defined port instead of TCP/1433.

Ports, cont’d

UDP/1434 can and should be blocked for production servers.

The server can be manually configured to listen on a port other than TCP/1433.

This will limit the effectiveness of worms attacking exposed servers.

Users and roles within SQL Server PUBLIC should be denied access to database objects.

Create new logins for your applications, and grant them rights to specific tables and other database objects.

Roles

Server roles sysadmin backup security admin

Database roles db owner db_datareader db_datawriter

SQL injection

Attacker sends arbitrary SQL commands through your application.

Attacker uses error messages (or simply times results) to determine success.

Demonstration

SQL injection attack

Input filtering

CFQUERYPARAM

Stored procedures

Resources

SQL Security:http://www.sqlsecurity.com/

MS Technet Security:http://www.microsoft.com/technet/security

DataDirect Connect for JDBC:http://www.datadirect-technologies.com/

Conclusion

If you have any questions, contact me:dwatts@figleaf.com

Thank you!