It was recently reported by Wired that a new technique employed by cyber criminals actually changes your bank statement to hide the fraudulent transfers from your bank account, this means that potentially you may be out of money for long enough and not know about it if you rely solely on your online statement and dont transact too much
link: http://www.wired.com/threatlevel/2009/09/rogue-bank-statements
This is the most troubling article I have read this weekend.
