Going where few password crackers have gone before, a team of security consultants has deployed a cracking-optimized computer that's completely submerged in mineral oil. Members say the setup offers significant cost savings compared with the same machine that uses air to stay cool.
The rig contains two AMD Radeon 6990 graphics cards, long considered a workhorse for password crackers. While the parallel processing in just one of these $800 cards can make as many as 9 billion password guesses each second (see PC3 in the graph at the bottom of this page), the performance comes at a price. GPUs run extremely hot, particularly when combined with other graphics cards, which drives up the cost of keeping them cool enough to run without burning out. The dedicated fans normally used to keep them cool also generate plenty of noise.
Employees of security consultancy KoreLogic recently deployed the password cracker at Midas Green Tech, an Austin, Texas-based data center that specializes in so-called immersion-cooled server hosting. Unlike the other air-cooled systems KoreLogic uses to test the strength of clients' password policies, the cost of hosting it is less than $60 per month, compared to about $100 for an air-cooled system, said Rick Redman, one of the KoreLogic penetration testers who deployed the new machine.