Oracle 9i on Windows 2003 -- Vulnerability Question

Hello,

I am trying to make our database more secure, one of the scenarios we came up is:
'what if an internal hacker (somehow) gets to our database server?'

1) what kind of damages he/she could cause, and 
2) what we need to do to protect our databases?
3) Could hacker be able to browse data?

Any article in this regard?

OS is Windows 2003, Oracle is 9.2.0.7.
The hacker has admin rights on the server.

Regards,
Estifan Panosian

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