A massive security breach of Marriott hotel’s Starwood reservation system has left the information of 500 million people exposed.

The hotels affected include W Hotels, St. Regis, Sheraton Hotels & Resorts, Westin Hotels & Resorts, Element Hotels, Aloft Hotels, The Luxury Collection, Tribute Portfolio, Le Méridien Hotels & Resorts, Four Points by Sheraton and Design Hotels. Starwood branded timeshare properties are also included.

This past September, the company realized that hackers had unauthorized access to the information of hotel guests for the past four years.  For over 300 million customers, hackers had access to information including names, mailing addresses, phone numbers, email addresses, passport numbers, Starwood Preferred Guest (“SPG”) 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.  Other guests only saw names and addresses exposed.

Marriott has begun emailing affected consumers. They’ve also set up a call center at the following numbers:

USA 877-273-9481
Canada 877-273-9481
UK 0-808-189-1065
Australia 1-800-270-917
Spain 900-905407
France 0805-080216
Germany 0800-180-1978
Italy 800-728-023
Russia 8-800-100-6925
Brazil 0-800-724-8312
India 000-800-050-1531
United Arab Emirates 8000-3201-34
Mexico 01-800-099-0742

Marriott will also pay for some affected customers to enroll in the Webwatcher credit monitoring service for one year. Users in the U.S., UK, and Canada can follow the links below for more information.