A gaping hole in Amazon.com's mobile application, now fixed, allowed hackers to have an unlimited number of attempts guessing a person's password, according to security vendor FireEye. If users enter their password incorrectly 10 times on the Amazon.com website, the company requires them to solve the squiggle of characters known as a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). The CAPTCHA is intended to thwart automated programs that will rapidly try different passwords.