  As more business activities are being automated and an increasing number of
computers are being used to store vital and sensitive information the need for
secure computer systems becomes more apparent. These systems can be achieved
only through systematic design; they cannot be achieved through haphazard
seat-of-the-pants methods.This paper introduces some known threats to the
computer security, categorizes the threats, and analyses protection mechanisms
and techniques for countering the threats. The threats have been classified
more so as definitions and then followed by the classifications of these
threats. Also mentioned are the protection mechanisms.
