In the past decade, the world's involvement with computers has exploded. With prices for memory becoming less expensive, and the power of processors increasing greatly. However, certain precautions must be made to protect information that is being created, stored and manipulated by computers. There are people in the communities all over the world, whether these communities include business or governments as well as single individuals looking to profit illegally, that want to hurt or disrupt business operations relating to computing. But, to protect information, users must have a basic understanding of how and why "crackers" invade systems and how to prevent this.
Let us first explain what threats there are to computers and what these threats affect. Many documents that are written on computers are made to be seen by only a few people. This is known as confidentiality. Exposure to these confidential documents could cause many adverse affects on the business leading to loss of competitive advantage to blackmail. "Crackers" often invade systems and disrupt data integrity by changing, adding or deleting data in databases or other applications. Finally, in regard to Internet servers and other servers there could be a denial of service attack. This type of attack overloads the host computer with requests thus taking all of the available CPU time and not allowing other users to gain access to the server. .
In response to these three threats to computers, there are two categories of intruders who break into computers. There are passive intruders, who are mainly concerned with the first threat stated, confidentiality. Passive intruders often read confidential information, and use it to their own advantage, while other times, it is nothing more than merely snooping around for curiosity sake. Active intruders on the other hand are more malicious; they actively change or delete data within the system.
