Two decades ago, Brain, the first boot sector virus that infected personal computers via the floppy disk, was detected. While Brain itself was relatively harmless, it marked the genesis of the world of computer viruses.
This year marks the 20th year of the existence of viruses after Brain was detected on January 19, 1986.
Boot sector viruses, now long extinct along with the floppy disk, held a relatively long reign from 1986 to 1995. Since transmission was via disk from computer to computer, infection would only reach a significant level months or even years after its release.
This changed in 1995 with the development of macro viruses, which exploited vulnerabilities in the early Windows operating systems. For four years, macro viruses reigned over the IT world and propagation times shrank to around a month from the moment the virus was found to when it became a global problem.
As e-mail became widespread, e-mail worms became the next menace, and some worms reached global epidemic levels in just one day. Most notable in this connection was one of the very first e-mail worms, Loveletter aka I LOVE YOU, which caused widespread havoc and financial loss in 1999 before it was brought under control.
In 2001, the transmission time window shrank from one day to one hour with the introduction of network worms (such as Blaster and Sasser), which automatically and indiscriminately infected every online computer without adequate protection. E-mail and network worms continue to cause havoc in the IT world.
At present there are more than 150,000 viruses and the number continues to grow rapidly. The biggest change over these 20 years has not been in the types of viruses or amount of malware; rather, it is in the motives of virus writers.
"Certainly the most significant change has been the evolution of virus writing hobbyists into criminally operated gangs bent on financial gain," said Mikko Hypponen, chief research officer of F-Secure, a security applications vendor based in Helsinki, Finland. "And this trend is showing no signs of stopping."
According to Hypponen, indications are that malware authors will target laptop WLANs next for automatic spreading worms. "Whatever the next step is, it will be interesting to see what kind of viruses we will be talking about in another 20 years time - computer viruses infecting houses, perhaps?"