Sony Pictures Entertainment warned both its current and former employees to beware of fraudsters who might be drawn to their personal information after a massive online security breach at the company in November. A hacking group called the "Guardians of Peace" (GOP) has claimed responsibility for the attack.

The company said that the hackers had access to classified employee information, such as social security numbers, credit card details, bank account information, health care information and salary and other employment-related data, Reuters reported. Late on Monday, Sony said that it is still investigating the scope of the cyberattack that targeted its computer systems last month. The company also said that its employees would soon be provided with identity-theft protection services.

On Monday, the hackers group said in a note that Sony employees could choose to avoid a leak of their personal data by simply requesting the group not to publish them.

"Message to SPE staffers," the hackers said in the note. "We have a place to release emails and privacy of the Sony Pictures employees. If you don’t want your privacy to be released, tell us your name and business title to take off your data."

However, the group also threatened to leak larger quantities of data in the coming weeks.

Last week, Sony asked certain media outlets to stop publishing information contained in the documents stolen by the hackers. Three news organizations, including the New York Times, The Hollywood Reporter and Variety, reported that they had each received a letter from an attorney for Sony, demanding that the publications stop reporting information contained in the documents. The letter also asked them to immediately destroy the leaked data.

Actors Seth Rogen and James Franco, the stars of the movie "The Interview," a comedy about a CIA attempt to assassinate North Korean leader Kim Jong-un, also blamed the media for making the leaked emails public.

"It's stolen information that media outlets are directly profiting from. It's ill-gotten gains," Rogen reportedly said, during a radio interview. "If the criminals could do that themselves, they would. But they can’t, so instead, the Wall Street Journal does it for them.”

According to one theory about what motivated the attack, North Korea may have encouraged GOP to launch an attack in retaliation for the Sony-backed movie, which is scheduled to release Dec. 25. The hacker group also has demanded that Sony cancel the movie's release but North Korea has denied supporting the cyberattack even while lauding it.