Think the Melissa virus was annoying? Consider this scenario: an employee at company X receives e-mail containing a snippet of virus code. The recipient opens the message, releasing the virus onto the hard drive, where it sits silently ... waiting. When the PC idles for an extended period, indicating that the employee has left for the day, the virus downloads another code, which sifts through the hard drive and forwards data to a remote site on the Net. If anyone touches the keyboard, the program shuts down and hides until the next opportunity to strike arrives.
I Spy
Until now, computer viruses have been more pesky than pernicious, vandalising data but rarely stealing it. Soon, experts say, spy viruses will be a real threat. Last June, antivirus companies learned of a virus that works through a screen saver called PrettyPark.exe. Click on the application, which comes as an e-mail attachment, and, if you're an mIRC user, the virus enters your computer to steal network passwords and other data, then attaches itself to outgoing e-mail.
Virile Viruses
Experts at Symantec and Network Associates say new viruses will study their host environments and alter themselves based on these. Last year, both companies reported an increase in the number of polymorphic viruses, those that change their code to evade detection. "For a virus to spread," says Jimmy Kuo, director of antivirus research for Network Associates, "it mustn't call attention to itself." That's why showy programs like Melissa, which make a lot of noise, do relatively little damage.
Kuo also reports a proliferation of data diddlers, viruses that undermine the integrity of data by randomly changing bits of it. One of these, called Compat, changes the values in an Excel spreadsheet to within 5 per cent of what they should be.
You can easily imagine the potentially destructive power of such a diddler. We wouldn't want one infiltrating our anaesthetist's computer, let alone the Pentagon's.
