According to a source, the motion picture giant's computer systems were shut down by a cyber intrusion on Monday.

A picture of a skeleton with message from the hackers saying "Hacked by #GOP" threatened to release the company's "top secrets".

A spokesperson for the corporation said of the incident: "Sony Pictures Entertainment experienced a system disruption, which we are working diligently to resolve".

Manual hijack of accounts leads to severe financial loss

Cybercriminals are now spending more time in devising targeted attacks on individuals to make significant financial gains instead of launching widespread automated attacks, says tech giant Google.

Incidents of manual hijacking -- where professional attackers spend considerable time exploiting a single victim's account -- are still rare at about nine incidents per million users per day, but the impact can be severely damaging, Google said in a study.
"The damage manual hijackers incur is far more severe and distressing to users and can result in significant financial loss," it added.
Google said these "needle-in-a-haystack" attacks are very challenging and represent an ongoing threat to Internet users.
Manual hijackers often get into accounts through phishing attacks by sending deceptive messages meant to trick users into handing over username, password and other personal information.
"Of the hijacking case samples we analysed, we found that most of the hijackers appear to originate from five main countries: China, Ivory Coast, Malaysia, Nigeria, and South Africa," it said.