photoWebcams connected to your computer allow you to communicate more directly with family and friends and set up an inexpensive security monitoring function. But they also have a dark side, security experts warn.

Hackers have developed malware and worms that can infect your computer and take control of your webcam. When you least expect it, your webcam could be watching you.

In 2004 hackers unleashed the W32/Rbot-GR worm, better known as the "Peeping Tom" virus, which exploited a number of Microsoft security vulnerabilities -- installing a backdoor Trojan horse. The security flaws have long been patched, but other versions of the bug are being turned out all the time.

"More and more hackers are interested in spying on the people they manage to infect with their worms and Trojan horses," said Graham Cluley, senior technology consultant for Sophos security software.

Why spy?

Why do hackers want to spy? In the workplace, the motivation might be industrial espionage. When they invade your home computer, the motivation is downright creepy.

"At home it is equivalent to a Peeping Tom who invades your privacy by peering through your curtains," Cluley said. "If your computer is infected and you have a webcam plugged in, then everything you do in front of the computer can be seen, and everything you say can be recorded."

After hackers infect a computer, they can gain access to the information on the PC's hard drive and steal passwords, which is what hackers typically do. But as more computers, especially laptops, come equipped with webcams, hackers have begun to take control of those as well, and use them to spy on unsuspecting victims.

Once in control of the camera, your every move could be under surveilance. The hacker can turn the camera on and off, take pictures and basically watch everything you do in front of your PC.

Instant messaging risk

Hijacking has become increasingly common among the people who use online instant messaging. If you don't have up to date security software, you could be especially vulnerable.

Also, unplug the camera or cover the lens when you aren't using the camera. Some of the newer webcams actually have a privacy shield that slides across the lens. If the camera is build into your computer, but you never use it, you can go into the computer set-up and disable it.

In early 2005, Spanish authorities fined a student who captured movie footage from unsuspecting users, and arrested a 37-year-old man who spied on victims via a webcam while stealing banking information. Last year a Rutgers University student committed suicide as his gay encounter with another student was secretly captured and broadcast using a webcam on a PC in the dorm room.

Since 2004, the webcam hijacking trend appears to be gaining ground.

"With many home users keeping poorly-defended PCs in their bedroom, there is considerable potential for abuse," Cluley said. "The message is simple: keep your PC protected against the latest threats with anti-virus software and firewalls, and if in any doubt unplug your webcam when you're not using it."