"Male. Obsessed with computers. Lacking a girlfriend. Aged 14 to 34. Capable of creating chaos worldwide."
The above description is profile of average computer-virus writer, according to Jan Hruska, chief executive of British-based Sophos PLC, world's fourth-largest anti-virus solutions provider.
"They have a chronic lack of girlfriends, are usually socially inadequate and are drawn compulsively to write self- replicating codes. It's a form of digital graffiti to them," Hruska added.
To create and spread cyber infections, virus writers explore known bugs in existing software, or look for vulnerabilities in new versions.
With more and more new OS (operating system) versions, there will be more new forms of viruses, as every single software or OS will carry new features, and new executables that can be carriers of infection.
Executables are files that launch applications in a computer's operating system, and feature more prominently in new platforms like Microsoft's Windows 2000 and Windows XP than they did in older DOS or Windows 3.1.
Virus writers also share information to create variants of same infection, such as Klez worm, which has been among world's most prolific viruses.
The Klez, a mass-mailing worm that originated in November 2001, propagates via e-mail using a wide variety of messages and destroys files on local and network drives.
But news gets worse. Recent events have uncovered what may be a new trend: spammers paying virus writers to create worms that plant an open proxy, which spammer then can use to forward spam automatically. Many suspect this occurred with SoBig virus.
The Sobig worms, began spreading in early part of 2003. The unusual thing about them was they contained an expiration date and were given a short life cycle to see how features worked in wild.
Having an expiration date also makes virus more dangerous, because most people would have been alerted to new worm within a few weeks and anti-virus definitions would have been updated.