Damage limitation: HBO conducts 'forensic review' of its computer systems

Damage limitation: HBO conducts 'forensic review' of its computer systems and hires firm to monitor employees' financial accounts after it was hit by hack 'SEVEN times larger than the Sony breach of 2014'

HBO boss told staff 'we do not believe' all emails were compromised in hack
But he could provide no concrete assurances amid ongoing 'forensic review'
He added that credit monitoring agency is being brought in amid fears that bank account details could have been stolen
Hackers are reported to have made off with 1.5 terabytes of information from HBO - six times as much as the Sony hack in 2014
Leak includes Game of Thrones scrips and episodes of Ballers and Room 104

Bosses at HBO are scrambling to reassure worried staff after hackers stole a huge amount of data from the company's servers.

CEO Richard Plepler sent a memo to employees on Wednesday saying 'we do not believe that our e-mail system as a whole has been compromised'.

But he provided no concrete assurances, saying that a 'forensic review' is still ongoing.

He also announced that a credit monitoring service is being brought in to monitor staff bank accounts amid fears that confidential details may have been stolen.

It comes after reports that hackers made off with seven times the amount of data stolen in the infamous Sony attack of 2014.

It was reported hackers broke into the cable company's servers earlier this week and made off with a script for this week's Game of Thrones episode, as well as unreleased episodes of Ballers, Room 104, and Insecure.

The show Barry, a comedy not set to hit screens until 2018, also had two episodes stolen.

It has now been reported the hackers who boasted about the attack went by the name 'little.finger66' - a reference to one of the characters in Game of Thrones.

Details published byVariety, indicate the hack could have gone much deeper than originally thought, and that information regarding a top HBO executive could have been be exposed.

Variety's report said that hackers published stolen information about the executive, including: 'information to dozens of online accounts, including paid newspaper subscriptions, online banking, and personal health services'.

The report then states: 'at least one of these accounts may also have given the hackers access to the executive’s work email'.

Variety's report goes on to cite a 'image file published as part of the leaks', saying it backs up the hackers initial claims that they stole 1.5 terabytes of data from the company.

If the figure of 1.5 terabytes, which is 1,500 gigabytes, it would dwarf the about 200 gigabytes of data was released online from the Sony hack.

The report added a security firm brought in by HBO to scrub the internet of the stolen files believes the hackers took 'masses of copyrighted items including... images, videos and sound' and 'thousands of internal company documents'.

That news, and the potential danger to a top executive, was not the only information about the hack published on Wednesday.

Another report, published by the Hollywood Reporter, went into alleged details regarding the sophistication of the attack.

THR cited industry insiders who claimed the hack was about 'targeting specific content and data housed in different locations', which would suggest there were 'multiple points of entry'.

The magazine claims in the update that the lack of any sort of ransom note or demands from the hackers is raising fears that: 'video footage, internal documents or even email correspondence could be leaked'.

Farsight Security CEO Paul Vixie told THR is the 1.5 terabyte figure is true, it could have taken the hackers multiple days to steal all the information.

'A traditional business-grade DSL link would take about two weeks at full blast to exfiltrate that much data,' Vixie told the magazine.

'If not for video and sound, a corporation the size of HBO might fit (entirely) in a terabyte, including all the email and spreadsheets ever written or stored.'

Ajay Arora, CEO of security firm Vera, was equally pessimistic when talking to the Reporter about what was potentially stolen.

'The entire Library of Congress is estimated to contain 10 terabytes of print content,' Arora said.

'As such, it's hard to believe that video and/or audio are not part of what was stolen. It will be interesting - and terrifying to HBO and their parent, Time Warner - to see what comes out.

The new information comes two days after details about the major hack were first reported by Entertainment Weekly on Monday.

HBO immediately consulted with law enforcement and cybersecurity firms to figure out the most effective and appropriate ways to handle the matter and possibly reprimand anyone found involved.

In a mass email to his employees, CEO Richard Pepler announced some of the network's programming was also stolen.

'Any intrusion of this nature is obviously disruptive, unsettling, and disturbing for all of us,' Pepler wrote in his email.

'I can assure you that senior leadership and our extraordinary technology team, along with outside experts, are working round the clock to protect our collective interests.

'The efforts across multiple departments have been nothing short of herculean.'

Pepler said he feels strongly HBO will get to the bottom of the breach with the efforts and teamwork of the company as a whole.

'The problem before us is unfortunately all too familiar in the world we now find ourselves a part of.

'As has been the case with any challenge we have ever faced, I have absolutely no doubt that we will navigate our way through this successfully.'