In general, database security is outside the scope of this document. Like all other systems used in your cloud deployment, you are expected to properly secure the vCloud Director database per industry best practices.

The vCloud Director database user account should have only the system privileges listed in the appropriate database configuration guidance in the vCloud Director Installation and Upgrade Guide. The vCloud Director database user should not be given privileges over other databases on that server or other system administration privileges. This would violate the Principle of Least Privilege on the database server and give the user more rights than necessary.

We recommend consulting the following documents for database security information.
Microsoft SQL Server
SQL Server Security Best Practices at http://download.microsoft.com/download/8/f/a/8fabacd7-803e-40fc-adf8-355e7d218f4c/sql_server_2012_security_best_practice_whitepaper_apr2012.docx.
Note: vCloud Director does not support SSL connections to a Microsoft SQL Server database.
Oracle
Oracle Database Security Guide at https://docs.oracle.com/cd/B28359_01/network.111/b28531.pdf.
Note: vCloud Director 9.5 does not support Oracle databases.

vCloud Director 9.1 supports Oracle databases, but does not support HTTPS and SSL connections to an Oracle database.

PostgreSQL
In addition to enabling SSL for PostgreSQL connections, we recommend reviewing the PostgreSQL Server Administration documents.