Sony is advising its current and former employees to be on the alert for fraudsters trying to use their stolen data, which included detailed personal information.
The company listed information like social security numbers, credit card details, healthcare information, compensation and bank account information and other employment-related data in what is Sony's most detailed description on the types of data stolen.
Sony's computer network was hacked last month and attackers have been releasing sensitive data over the internet since. A group called the Guardians of Peace claimed responsibility for the cyber-attack, which forced the company to shut down most of the studio's network for more than a week, according to Reuters.
In a memo sent to staff on Dec. 2, Sony acknowledged a large amount of data as stolen by hackers, but declined to confirm what documents had been accessed by the hackers.
Sony is currently in the middle of investigating the scope of the cyber-attack and is trying to notify all employees that it would be providing identity theft protection services.
Sony Pictures has also provided a toll-free number for all potentially affected people to call to get more information about identity protection services available.
The studio is expected to face tens of millions of dollars in costs due to the massive computer hack that halted its operations and exposed sensitive data.
The cost should be less than the $171 million Sony estimated for the breach of its PlayStation Network in 2011 since it doesn't look like it involves customer data, experts to Reuters.
It normally takes around six months after a breach to determine the full financial impact, said Jim Lewis, senior fellow at the Center for Strategic and International Studies.
The group responsible for the attack uploaded yet-to-be-released Sony films like the upcoming holiday musical "Annie," which hits theaters on Dec. 19.