Hackers from Rex Mundi claim they were able to access a database which is shared by Domino's France and Domino's Belgium and have stolen the details of more than 650,000 customers.
The group is threatening to put the information, which includes customers' topping preferences, on the Internet unless the pizza chain forks over 30,000 euros ($40,590).
Rex Mundi turned up the heat on Domino's by posting about their scheme on dpaste.de.
"Earlier this week, we hacked our way into the servers of Domino's Pizza France and Belgium, who happen to share the same vulnerable database. And boy, did we find some juicy stuff in there!" Rex Mundi wrote.
"We downloaded over 592,000 customer records (including passwords) from French customers and over 58,000 records from Belgian ones. That's over six hundred thousand records, which include the customers' full names, addresses, phone numbers, email addresses, passwords and delivery instructions."
The group set a deadline of Monday evening and also provided examples of the kind of information that will be delivered to the web if Domino's doesn't pay.
"We have already contacted our clients with the advice," Domino's Pizza executive Andre ten Wolde told Belgian newspaper De Standaard. "There are clear indications that something is broken on our server. The information contained in them, are protected...Financial data, such as credit cards are not stolen. "
Domino's France also acknowledged the breach on Twitter.
Domino's Pizza utilise un système de cryptage des données commerciales. Toutefois les hackers dont nous avons été victimes 1/4— Domino's France (@dominos_pizzafr) June 13, 2014