A juicy new tidbit has been discovered as part of the massive hack of Marriott we told you about just a week ago that included an unauthorized party gaining access to the hotel's Starwood guest reservation database in September.
Private investigators found hacking tools, techniques and procedures that featured in past attacks attributed to Chinese hackers, according to the report.
These clues suggest Chinese hackers could have orchestrated a campaign with the intention of harvesting data for Beijing's espionage efforts, said the unnamed sources. They also noted that someone else could also have launched the attack because some of the same hacking tools used in the attack were previously made accessible online.
About 327 million out of 500 had a combination of name, mailing address, passport number, Starwood Preferred Guest account information, date of birth, gender, arrival and departure information, reservation date, and communication preference accessed.
But the sources told Reuters it's also hard to lay the blame directly at China's feet because they suspect multiple hacking groups have been inside the Starwood system since 2014.
China foreign ministry spokesman Geng Shuang, speaking at a regular press briefing Thursday, said that while he wasn't aware of the specific case, "I believe China firmly opposes and cracks down on all forms of hacking".
Another reason for suspicion of China is that the timing of the initial breach in 2014 was right around the time, according to USA intelligence, that the country's operatives began poking around in the systems of the Office of Personnel Management.
The attackers also would have been able to look at information on when customers stayed with the hotels, though that info would have been of far less value. Theoretically, cross-referencing that kind of information with hotel and travel records could yield intelligence benefits.
"Our primary objectives in this investigation are figuring out what occurred and how we can best help our guests", a Marriott spokesperson told Bloomberg News by email.