A group calling itself Lulz Security said it took passwords, email addresses, birthdates and more to highlight Sony Picture's "disgraceful" security.
In a statement, Sony Pictures leaders acknowledged the breach and said the company had taken action "to protect against further intrusion."
"We have also retained a respected team of experts to conduct the forensic analysis of the attack," the statement said. It did not go into details about specific actions that will be taken to prevent future security breaches.
It wasn't clear how many people were affected. The hackers boasted of compromising more than 1 million users' personal information - although it said that a lack of resources meant it could only leak a selection on the Web.
This comes just weeks after another massive cyber breach on the company's PlayStation network, in which millions of credit card numbers were taken.