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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/
