Security Experts:

Vulnerability in Marriott Mobile App Exposed Customer Details

Up until last week, it was easy for a malicious hacker to gain access to the reservations and personal details of Marriott customers by leveraging a vulnerability in the hotel chain’s official mobile application.

The issue was discovered by software developer and security researcher Randy Westergren, who recently identified a vulnerability that exposed the email accounts of Verizon customers.

Westergren uncovered the security hole while analyzing Marriott International’s Android app. The expert noticed that no authentication mechanism had been used when fetching reservation details from the server.

By simply changing the membership ID (rewards number) in the request, the researcher could query the reservation of any member of Marriott’s rewards program. The response from the server contained information such as hotel name, check-in date, reservation ID, and the guest’s last name.

The problem, as highlighted by Westergren, is that users who want to manage their reservations on the Marriott website only need the reservation ID and the last name, pieces of information provided in the response from the server.

A hacker could have canceled a user’s reservation, and he could have accessed a page containing the victim’s personal information, including their name, email address, rewards number, address, the last four digits of the payment card number, and card expiration date.

“Obviously, this was a very serious vulnerability,” Westergren wrote in a blog post.

The details of the flaw along with a proof-of-concept (PoC) were sent to Marriott on January 20. The hotel chain’s security team fixed the vulnerability by the next day. However, the researcher noted that it took him more than a month to get in touch with the right person at Marriott.

In October, the Federal Communications Commission (FCC) slapped the hotel chain with a $600,000 fine for using its Wi-Fi monitoring system to block the guests of certain conference facilities from accessing the Web through their personal hotspots.

The company defended its practices by saying that it had blocked unknown hotspots in an effort to protect customers against rogue wireless networks.

Marriott and the American Hospitality and Lodging Association petitioned the FCC last year to allow blocking. Following protests from Microsoft, Google and others, Marriott backed down and promised not to block guests from using their personal Wi-Fi devices at any of its hotels.

“Marriott remains committed to protecting the security of Wi-Fi access in meeting and conference areas at our hotels,” Marriott said in a statement on January 14. “We will continue to look to the FCC to clarify appropriate security measures network operators can take to protect customer data, and will continue to work with the industry and others to find appropriate market solutions that do not involve the blocking of Wi-Fi devices.”

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.