A hacker guessed a promotional coupon code that authorized a free medium one-topping pizza and publicized the code, which got used about 11,000 times in 48 hours, according to Jeremiah Grossman, founder and CTO of White Hat Security, who will deliver the talk.

Patrons ordering pizza online would put in their order then enter the code, essentially a password, into the "coupon" field on the site, he says.

The Domino's incident is one of about a dozen examples of how people can make money -- not necessarily legally -- off the Internet that Grossman will discuss in his briefing, called "Mo' Money Mo' Problems: Making A LOT More Money on the Web the Black Hat Way".

The person who guessed the Domono's password -- BAILOUT -- was never caught, Grossman says, and the promotion had been set up in the chain's system without getting the go-ahead. Many businesses authorize their marketing departments to set up such promotions from their network security teams so they often lack anti-brute-force protections and lockouts, he says.