Endoflow2010 writes "Hackers who stole the personal details of more than 200,000 Citigroup customers 'broke in through the front door' using an extremely simple technique. It has been called 'one of the most brazen bank hacking attacks' in recent years. And for the first time it has been revealed how the sophisticated cyber criminals made off with the staggering bounty of names, account numbers, email addresses and transaction histories. They simply logged on to the part of the group's site reserved for credit card customers and substituted their account numbers — which appeared in the browser's address bar — with other numbers. It allowed them to leapfrog into the accounts of other customers, with an automatic computer program letting them repeat the trick tens of thousands of times."