Marriott Discloses Breach of 500M Guest Records, Dating Back to 2014

In one of the largest breach disclosures in recent memory, Marriott International has revealed that its Starwood Hotels division had been breached since 2014, leaving customer data including payment card information at risk.


There have been multiple cyber-security incidents in recent years involving hotel chains, but none has been bigger than the one disclosed on Nov. 30 by Marriott International's Starwood Hotels and Resorts division.

Information from approximately 500 million individuals who have made reservations at Starwood properties around the world are potentially at risk from the massive data breach disclosed by Marriott. Detailed information on 327 million individuals, including name, mailing address, phone number, email address, passport number and data of birth, was stolen in the breach. Additionally, payment card information including numbers and expiration dates was stolen from an undisclosed number of impacted Starwood guests.

"We deeply regret this incident happened," Arne Sorenson, Marriott's president and CEO, wrote in a statement. "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."

While the number of impacted consumers in the Marriott breach is staggering, the timeline for disclosure in the security incident adds further insult to injury. According to Marriott's investigation, attackers have had unauthorized access to the Starwood network since 2014.

Although attackers had been in the system for four years, it wasn't until Sept. 8 of this year that Marriott saw an alert from one of its internal security tools, which triggered the investigation that ultimately discovered the unauthorized access. While the alert was triggered in September, it wasn't until Nov. 19 that Marriott formally made the determination that attackers had in fact copied information from the Starwood network. The attackers encrypted the copied information, and apparently it took Marriott several months to investigate and decrypt the data to make a positive determination that the data was from the Starwood guest reservation database.

Marriott has also not conclusively determined at this point how much payment card information was stolen. According to Marriott, the payment card information in its database was encrypted with a system that requires two different components in order to decrypt the payment card numbers.

"At this point, Marriott has not been able to rule out the possibility that both were taken," Marriott stated in an advisory.

The Starwood brands hotels involved in the data breach 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. 

Past Attacks

This is not the first time Starwood Hotels has been involved in a data breach. In November 2015, Starwood reported that it was the victim of data breaches affecting 54 of its properties in the United States and Canada. Other hotel chains, including Hilton and Hyatt, also disclosed data breaches in 2015 and in 2016.

Marriott acquired Starwood in 2016. Jeff Pollard, vice president and principal analyst at Forrester, commented that while Marriott and Starwood merged in 2016, this breach goes back to 2014. 

"Since Marriott properties were not affected, this appears to have been solely a Starwood incident," Pollard said. "That means it also went undetected during the merger and subsequent consolidation efforts."

Pollard added that the breach highlights the importance of robust cyber-security due diligence during the acquisition process. 

"Marriott now faces brand and reputational damage, regulatory oversight and legal issues as the result of a cyber-security incident that occurred two plus years before they announced the acquisition of Starwood," he said. "This reinforces the point Forrester often makes that cyber-security breaches have a long tail, and this one will lead to unanticipated costs for Marriott.” 

Sean Michael Kerner is a senior editor at eWEEK and Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.