•For example, a student with an infected applications disk might infect several other laboratory computers with a virus which, in turn, infects the applications software of other students.
•Software companies have unknowingly distributed viruses with their proprietary software products.
In the mini-computer and …
•Main-frame environment, viruses generally are spread from one computer network to another.
•In late 1988 a Cornell graduate student wrote a costly virus (causing over $ 20 million in damages) that infiltrated 6000 computer on six continents via worldwide computer network.
Since first appearing in …
•The mid-1980s, viruses have erased bank records, damaged hospital records, destroyed the program in thousands of micro-computers, and even infected part of the systems at NORAD (strategic defense) and NASA.
•Disgruntled employee have inserted viruses in disks that were distributed to customers.
