Why E-Mail-Borne Viruses Have Become So Dangerous

Before Internet use became pervasive, viruses spread relatively slowly. Since they usually propagated via floppy disks, they often took weeks or months to spread widely. This made it relatively easy to identify virus attacks and to take precautions before viruses could do much damage. Typically, only a few of an organization’s PCs were affected before a virus attack was halted.

During the pre-Internet era, most organizations felt that the low cost and high popularity of inherently insecure operating systems, such as MS-DOS, Windows 3.x/9x, and Macintosh, outweighed the risks of virus damage. While more secure desktop operating systems, such as Unix and Windows NT, were available, most home users and organizations did not experience enough security problems to justify the higher cost and complexity of these operating systems. When high security was truly needed, such as in financial institutions, most organizations relied on terminal sessions that accessed applications running on mainframes or minicomputers.