Show organizers offered a Sony Vaio, Fujitsu U810 and the MacBook as prizes

Nobody was able to hack into the systems on the first day of the contest

on Thursday the rules were relaxed

The MacBook was the only system to be hacked by Thursday

Miller, a former National Security Agency employee best known as one of the researchers who first hacked Apple's iPhone last year, didn't take much time.

Within 2 minutes, he directed the contest's organizers to visit a Web site that contained his exploit code, which then allowed him to seize control of the computer

In 2005, he earned $50,000 for a Linux bug he delivered to an unnamed government agency.

Last year's contest winner, Dino Dai Zovi, exploited a vulnerability in QuickTime to take home the prize.

Terri Forslof, TippingPoint's Manager of Security Response

expects both systems

Linux and Vista

to be hacked on Friday,