Marriott disclosed a breach of its Starwood reservation database that potentially affects an estimated 500 million guests.

Details of the Marriott data breach, which goes back to 2014, have been reported to law enforcement and regulatory authorities, according to the company. Marriott said it received an initial alert on Sept. 8 that an unauthorized third party had attempted to access the Starwood database. Further investigation revealed that an unknown entity copied and encrypted guest information and also attempted to steal the database. The public first learned of the data breach when it was disclosed on Nov. 30.

What Personal Information Was Stolen?

Although the company stated that it had not finished decrypting the copied information at the time of disclosure, it confirmed that the personally identifiable information (PII) of approximately 327 million people might have been comprised. The data includes payment card numbers and expiration dates, though it is not yet known if the two keys needed to decrypt the Advanced Encryption Standard (AES-128) protocol used to protect this information were also stolen.

In addition to payment card information, threat actors also accessed the 327 million customers’ names, passport numbers, Starwood Preferred Guest account information, dates of birth, genders and email addresses. For the remaining guests, the information was limited to names and mailing or email addresses.

The Marriott incident is one of the largest in history, and could be one of the first opportunities for European Union regulators to flex their General Data Protection Regulation (GDPR) muscles. The GDPR was enacted in late May, promising severe fines for violations of data privacy and disclosure.

Response to the Marriott Data Breach

Since the Marriott data breach was disclosed, two class-action lawsuits seeking damages for the exposure of personal information have been filed. Multiple news outlets, including The New York Times, have reported that the Federal Bureau of Investigation (FBI) is tracking the situation, and investigations have been launched by attorneys general in several states.

Customers affected by the Marriott data breach can access a dedicated website and call center with any questions. The company is also offering guests a free year of the WebWatcher monitoring software to help identify any misuse of personal information.

Of course, Marriott is far from alone in dealing with large data breaches. According to Ponemon’s “2018 Cost of a Data Breach Study,” the number of mega breaches — those involving more than 1 million records — has nearly doubled from 2013 to 2017.

Sources: Marriott, ZDNet, The New York Times