The US Attorney’s Office for the Southern District of New York announced seven criminal counts against Mesri over the hack which occurred in August.
Mesri is in Iran and is thus unlikely to be apprehended unless he happens to travel to a country which has an extradition treaty with the US.
Acting Manhattan US Attorney Joon Kim said: “Behzad Mesri, an Iranian national who had previously hacked computer systems for the Iranian military, allegedly infiltrated HBO’s systems, stole proprietary data, including scripts and plot summaries for unaired episodes of Game of Thrones, and then sought to extort HBO of US$6 million in bitcoin.
"American ingenuity and creativity is to be cultivated and celebrated - not hacked, stolen, and held for ransom. For hackers who test our resolve in protecting our intellectual property — even those hiding behind keyboards in countries far away — eventually, winter will come.”
At the time when the stolen files were leaked on the Web, the attackers also released details of how they had gained access.
The hackers claimed they had needed about six months to penetrate the HBO network and that they were paying about US$500,000 annually to buy zero-day exploits for software from Microsoft and other companies.
According to the indictment, "from approximately May 2017 to July 2017, Mesri successfully compromised multiple user accounts belonging to HBO employees and other authorised users, and used those accounts to repeatedly obtain unauthorised access to HBO’s computer servers.
"Over the course of several months, Mesri used that unauthorised access to steal confidential and proprietary information belonging to HBO, which he then exfiltrated to servers under his control.
"Through the course of the intrusions into HBO’s systems, Mesri was responsible for stealing confidential and proprietary data belonging to HBO, including, but not limited to: (a) confidential video files containing unaired episodes of original HBO television programmes, including episodes of Barry, Ballers, Curb Your Enthusiasm, Room 104, and The Deuce; (b) scripts and plot summaries for unaired programming, including but not limited to episodes of Game of Thrones; (c) confidential cast and crew contact lists; (d) emails belonging to at least one HBO employee; (e) financial documents; and (f) online credentials for HBO social media accounts."