HBO CEO Richard Plepler does not believe the company’s email system was compromised. The company is investigating the breach with outside security firms and law enforcement to determine the extent of the attack. The unknown hacker(s) behind the breach claim to possess 1.5 terabytes of data. If true, this would make the HBO incident significantly bigger than the 2014 Sony hack in which attackers leaked 200GB of information. The Hollywood Reporter obtained an email from the alleged hacker who calls himself Kind Mr. Smith and claims he will release evidence of his access to HBO emails.”]
Source: https://www.darkreading.com/attacks-breaches/hbo-breach-did-not-compromise-full-email-system-ceo