Mariottt International has suffered what can be considered one of the largest data breaches in history, trailing only the 2013 Yahoo breach. The world’s largest hotel chain said some 500 million customer records were compromised.
In a notice on its website, Mariott International said in early September it received an alert from an internal security tool pointing to “an attempt to access the Starwood guest reservation database in the United States.” Mariott bought Starwood in 2016 for $12.2 billion.
“Mariottt learned during the investigation that there had been unauthorized access to the Starwood network since 2014,” the hotel chain said. “The company recently discovered that an unauthorized party had copied and encrypted information, and took steps towards removing it. On November 19, 2018, Mariottt was able to decrypt the information and determined that the contents were from the Starwood guest reservation database.”
Mariott believes hackers compromised approximately 500 million guest records. For approximately 327 million of those who made a reservation at a Starwood property, the information believed to be compromised includes some combination of name, mailing address, phone number, email address, passport number, Starwood Preferred Guest (“SPG”) account information, date of birth, gender, arrival and departure information, reservation date, and communication preferences, the notice said.
For some customers, the leaked data also includes encrypted payment card numbers and payment card expiration dates.
“There are two components needed to decrypt the payment card numbers, and at this point, Mariottt has not been able to rule out the possibility that both were taken,” reads the warning.
Mariottt has posted an FAQ page and has opened a dedicated call center to help affected customers. The hotel chain is also providing one full year of Internet monitoring through WebWatcher.
“We deeply regret this incident happened,” said Arne Sorenson, Mariottt’s President and Chief Executive Officer. “We fell short of what our guests deserve and what we expect of ourselves. We are doing everything we can to support our guests, and using lessons learned to be better moving forward.”
Mariott risks hefty fines if the compromised customer data includes information of European Union residents – which it likely does. Under the General Data Protection Regulation, the EU can fine Mariott the equivalent of 4% of its annual turnover.
A Quartz report listing the 20 largest data breaches by number of compromised records ranks the Mariott hack second, just behind the Yahoo 2013 incident that saw 3 billion customer records compromised.