Oracle RDBMS Server Default Account Vulnerability
Oracle RDBMS Server is a fully-featured relational database management system. Oracle RDBMS provides a set of administrative tools for the Oracle database. Oracle is available for the Unix, Linux, and Microsoft Windows platforms.
In default installations of the Oracle database, the RDBMS Server installs a number of "demo" accounts with preset passwords. Remote attackers who are aware of the default accounts may use them to gain unauthorized access to the database.
Some of these default accounts are required by the database, others present a security vulnerability.
This has been a known issue for quite some time.