Viruses - How Viruses Work, Types Of Viruses, Fending Off Viruses

Viruses are computer programs, usually malicious but occasionally unintentional, that spread through networks replicating themselves on shared programs and corrupting the computers in their path. While viruses have existed for years, they have taken on a new prominence and danger in the Internet Age, when they can spread much faster and compromise more—and more important—systems. A vast industry arose to combat viruses, but it was largely engaged in an arms race in the early 2000s, as viruses continued to proliferate and mutate, growing more powerful and damaging.

Since computers and networking have become such a central component of economic and social activity, virus attacks, even relatively minor ones, have the potential to severely disrupt daily life. Out of that growing recognition, governments, corporations, and organizations, were coordinating efforts to prepare for and respond to computer viruses.

In a 2001 report titled Virus Prevalence Survey, the Reston, Virginia-based Internet security assurance firm ICSA.net reported that the number of companies that experienced major virus-related disasters increased more than 20 percent in 2000, while 40 percent of companies reported data losses from virus attacks. The report also noted that a typical company spent between $100,000 and $1 million on virus disasters and protection each year, and that figure was rising.

ICSA reported that the prevalence of virus attacks has increased from about 10 per 10,000 computers in 1996 to 91 per 10,000 in 2000, and analysts warned that the proportion would rise in the early 2000s. To make matters worse, each generation of viruses grows more sophisticated. In the early 2000s, virus hunters were challenged by new breeds of self-replicating and mutating viruses that change shape as they spread so as to avoid detection. Virus programmers increasingly incorporate encryption schemes into the programs so as to shield the source code, and metamorphic viruses include a mutation engine in their algorithms that enable them to alter slightly at each replication.