Avoiding Twitter hacks, Koobface, and other security holes

The messages are sent by friends, family, and trusted acquaintances. Some appear to carry embedded images or videos. Most arrive under innocuous subject lines: "You look just awesome in this new movie," or "Funny moments."

But when users of popular social networks Facebook, MySpace, and Bebo click on the link inside the message, they set loose a devastating computer virus called Koobface, which devours their operating systems from the inside out. According to research conducted by Kapersky Lab, a digital security group, Koobface quickly turns computers into highly infectious "zombies," which spread the virus outward in an ever-widening spiral.