earlier, internal crime is much more prevalent than external crime. In fact, data security consultants often work under the assumption that in any given employee population, 25 percent will be honest, 25 percent will be dishonest, and the remaining 50 percent could be tempted to steal if given the opportunity.
The most elementary security precautions can often prevent internal security breaches. For instance, a company should only give an employee access to those parts of the computer system that are necessary to do his particular job and should isolate and lock up any machines that perform critical or sensitive tasks. Software packages which restrict access to a mainframe are currently available, although they cost approximately $35,000 per copy. Such packages are most often used by those companies with the most to lose from computer crime, like banks. However, it is interesting to note that, according to market research firm Computer Intelligence, only 10 percent of IBM mainframes had data security software in 1982 but by 1988, fully 35 percent had it.
A company seeking to prevent internal computer crime should also change passwords frequently and forbid the use of easily guessed passwords such as a birthday or spouse's name. Surprisingly, even NASA admits that having common passwords of this sort was part of the reason that its network was so easily penetrated in the Fall of 1987 - a case which will be discussed more later. Prohibitting employees from logging on and leaving their terminals unattended, sharing their personal passwords with coworkers, and using untested software which might contain a virus are a few other basic security strategies which effectively prevent employee computer crime. Many companies which have been the victims of such crime had neglected these precautions, which is why experts agree that computer security is largley a management problem, not a technical problem.
There are, however, a...