Marriott International revealed its database of guest information had been hacked at the end of November, 2018.
Private investigators examining the breach have uncovered “hacking tools, techniques and procedures” suggesting China’s involvement.
Friday, Marriott announced that roughly 5.25 million unencrypted passport numbers were among the stolen data.
Revising its initial victim count of 500 million downwards, the company offered a new estimate of less than 383 million.