German security researcher Thomas Roth has created a program that runs on Amazon’s Elastic Cloud Computing (EC2) system. It uses the massive computing power of EC2 to run through 400,000 possible passwords per second. The program generates millions of passphrases, encrypts them, and sees if they allow access to the network. EC2 computers used in the attack cost 28 cents per minute, so $1.68 is all it could take to lay open a wireless network. It’s claimed that up to 20 characters are enough to create an uncrackable passphrase.
Source: https://thehackernews.com/2011/01/cloud-computing-used-to-hack-wireless.html