This is something for Xbox Live gamers to think about, especially if they also have computers connected to the home network. If the Xbox Live users at your house are particularly feisty or contentious, they could get booted out of games by hackers who have figured out how to get the offending gamer's IP address. They then use that address to launch a kind of denial-of-service attack that blocks your gamer's access to the game, the BBC reports. It could also affect other Internet connections on the network. "Microsoft is 'investigating' the use of the tools and said those caught using them would be banned from Xbox Live. One preventive measure is try to get Xbox Live users at your house to "play nice." If they do and they still get booted, those are really malicious hackers. Definitely contact Xbox Live customer support! Another security issue this week is the reemergence of the Koobface worm in Facebook and MySpace. Brian Krebs of the Washington Post cites TrendMicro as explaining that what happens is, social networkers get an invitation from a friend or contact, inviting them "to click on a link and view a video at a counterfeit YouTube site." Then they're told they "need to install an Adobe Flash plug-in to view the video," but what they really download, if they fall for it, is a Trojan horse program that lets attackers take over their computer.