Marriott has said it has taken measures to investigate and address a data security incident involving the Starwood guest reservation database.
As many as 500 million guests might have been impacted by the incident, with credit card, address and other details potentially compromised.
The company revealed today that there was “unauthorised access to the database”, which contained guest information relating to reservations at Starwood properties on or before September 10th.
On September 8th, Marriott received an alert from an internal security tool regarding an attempt to access the Starwood guest reservation database in the United States.
The company then engaged security experts to help determine what occurred.
Marriott learned during the investigation that there had been unauthorised access to the Starwood network since 2014.
The company recently discovered that an unauthorised party had copied and encrypted information, and took steps towards removing it.
On November 19th, 2018, Marriott was able to decrypt the information and determined that the contents were from the Starwood guest reservation database.
“We deeply regret this incident happened,” said Arne Sorenson, Marriott president.
“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.”
The company has not finished identifying duplicate information in the database, but believes it contains information on up to approximately 500 million guests who made a reservation at a Starwood property.
For approximately 327 million of these guests, the information includes some combination of name, mailing address, phone number, email address, passport number, Starwood Preferred Guest account information, date of birth, gender, arrival and departure information, reservation date, and communication preferences.
For some, the information also includes payment card numbers and payment card expiration dates, but the payment card numbers were encrypted using Advanced Encryption Standard encryption.
There are two components needed to decrypt the payment card numbers, and at this point, Marriott has not been able to rule out the possibility that both were taken.
For the remaining guests, the information was limited to name and sometimes other data such as mailing address, email address, or other information.
Sorenson added: “Marriott is reaffirming our commitment to our guests around the world.
“We are working hard to ensure our guests have answers to questions about their personal information, with a dedicated website and call centre.
“We will also continue to support the efforts of law enforcement and to work with leading security experts to improve.
“Finally, we are devoting the resources necessary to phase out Starwood systems and accelerate the ongoing security enhancements to our network.”
Marriott reported this incident to law enforcement and continues to support their investigation.
The company has begun notifying regulatory authorities.