Marriott Concedes 5 Million Passport Numbers Lost to Hackers Were Not Encrypted - The New York Times
►https://www.nytimes.com/2019/01/04/us/politics/marriott-hack-passports.html
What made the Starwood attack different was the presence of passport numbers, which could make it far easier for an intelligence service to track people who cross borders. That is particularly important in this case: In December, The New York Times reported that the attack was part of a Chinese intelligence gathering effort that, reaching back to 2014, also hacked American health insurers and the Office of Personnel Management, which keeps security clearance files on millions of Americans.