**6. Conclusion**

A lot of computer threats have been included in this chapter with many terms tending not to be mutually exclusive. Again, an attack may get classified into different classes since attackers use multiple techniques or strategies. The irony is that even with lot of advanced defensive mechanism put in place by security experts, the hackers may still use the same attacking techniques and will take advantage of the same vulnerabilities they have used in the past. It is important to defend the attacks by paying attention to the internal systems, deploying multiple defenses for enhanced security, and avoiding irreparable damage. This requires the implementation of security policy as an ongoing process with tight access control mechanism and deployment of advanced multiple layer security devices.
