January 25, 2006 This month sees the 20th birthday of the PC computer virus – Brain. Brain was a boot sector virus that first emerged in January 1986, propogated via floppy disk and was relatively innocuous in contrast to modern computer afflictions. Brain was not the first computer virus – that was written by University of Southern California PhD student Fred Cohen for a Vax mini computer, with Cohen presenting his findings to a security seminar in November, 1983. Brain was the first virus written for a Personal Computer and it targeted the newly released IBM PC. As the internet has networked the world, file sharing and hence computer viruses have become commonplace with rapid propogation that can often cause havoc within hours. Such viruses have become modern scourges, with their names known to millions: Melissa, the LoveBug, Sobig, and Code Red. The world’s first mobile phone virus was detected in June 2004 – (a “worm” known as Cabir which infects Symbian OS phones and devices) and as home networks proliferate, it is quite possible that your house will one day be infected.

While the virus Brain itself was relatively harmless, it set in motion a long chain of events leading up to today’s virus situation.

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 when the virus was found to when it was a global problem.

As email became more widespread, so followed email worms and individual worms which reached global epidemic levels in just one day. Most notable in this connection was one of the very first emails worms, Loveletter aka ILOVEYOU, 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. Email and network worms still continue to cause havoc in the IT world today.

At present there are over 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 has been in the motives of the virus writers.

“Certainly the most significant change has been the evolution of virus writing hobbyists into criminally operated gangs bent on financial gain,” says Mikko Hypponen the Chief Research Officer at anti-virus software company F-Secure. “And this trend is showing no signs of stopping.”

“There already are indications that malware authors will target laptop WLANs as the next vector for automatic spreading worms. Whatever the next step might be, it will be interesting to see what kind of viruses we will be talking about in another twenty years time – computer viruses infecting houses, perhaps?”

These days it is imperative that a computer has antivirus software installed. Trend Micro PC-cillin Internet Security, Symantec's Norton Antivirus and Network Associates' McAfee VirusScan are the top selling software in the area.

To learn more about viruses and worms, might we suggest you begin here.