SIKESTON -- Computer users who forgot to update their anti-virus programs before midnight today should think twice before opening any e-mails with suggestive subject lines, especially if they want to keep any existing files.
Another Internet worm is wriggling its way through computers, and this time the virus, commonly known as Kama Sutra, is programmed to start deleting different types of vital files on the first Friday of the month, beginning today.
"It gets on computers by opening an attachment on an e-mail," said Tony Nickens, computer technicican/security specialist for Advanced Computer Systems in Sikeston.
The worm is tricking users by appearing as an e-mail with subject lines like "the best videoclip ever," "give me a kiss" and "school girl fantasies gone bad."
The payload, or major purpose, of the worm is to delete the most common file tips including those ending in ".pdf," ".doc," ".zip," Nickens said. In addition to deleting files, the worm also disables anti-virus programs once the virus is in the computer.
"It's the type of worm that if you get it, odds are you'll hit 15 or 16 others (worms). It calls all its buddies and says, 'Look here. We've got lunch,'" Nickens said.
The worm is also known as "Blackmal", "Nyxem-D" and "W32.Blackmail.E," among others, and is an operating system-based virus.
"The problem is when the virus deletes the files, it doesn't delete them so you can recover them from the trash bin. And the odds are you are not going to get your information back," Nickens said.
Nickens said the best prevention method would have been to back up all crucial files and ensure all anti-virus software was current before midnight today.
"Anyone who has ever played with a computer in a professional capacity probably doesn't open e-mails from people they don't know, especially attachments," Nickens said.
But not everyone heeds that advice.
Once a computer is infected, it can be real expensive to get the system corrected, Nickens said.
"You're still looking at hours of reinstalling printer software, scanner software and any software to do with a DVD player and added drives," Nickens said.
He added users don't necessarily have to send their computers to a service center if they know how to fix their computers.
Security vendors Trend Micro Inc. and CA Inc. both assessed the overall risk and distribution as low. The worm wasn't expected to spread any more quickly today. Rather, today was the first trigger date for the file-destroying code.
''It's well past the deadline but we haven't confirmed any cases of the Kama Sutra in Japan, which suggests we're not looking at a major outbreak,'' said Itsuro Nishimoto, an executive at Tokyo-based computer security company LAC Corp.
Unlike other worms generally designed to help spammers and hackers carry out attacks, Kama Sutra could inflict more damage because it sets out to destroy documents.
''This virus is nowhere near as widespread as some of the (recent virus) cases,'' said Mikko Hypponen, chief research officer for Finnish security company F-Secure Corp. ''The reason it's talked about is because it's more destructive.''
He said damage is high among those hit, but many businesses should already be protected by antivirus software. Home users and smaller companies without the latest software updates may be more vulnerable.
"It's a major problem when that payload will eat files, and there's no recovery. It opens the computer up to other security issues," Nickens said.
Nickens said the Kama Sutra worm is comparable to the Sasser worm -- a computer worm that caused major damage across the world a couple of years ago.
"It's in that league," Nickens said.
Nickens recommended the following Web sites for updates and more information: www.sarc.com, www.symantec.com and www.microsoft.com.
The Associated Press contributed to this report.