Attila Nemeth, 26, from Hungary, has pleaded guilty in U.S. District Court to hacking and extortion charges. He placed backdoor malware on Marriott computers, exfiltrated sensitive documents, and then threatened Marriott with exposing the information. Nemeth’s methods were similar to those of advanced persistent threat (APT) attackers: He got a foot in the door of Marriott’s computers by targeting some of its employees with spear-phishing emails. Marriott did not publicize details about what happened next, but one or more of the users appear to have fallen for the emails.”]
Source: https://www.darkreading.com/attacks-breaches/marriott-hacker-s-blackmail-goal-an-it-job