A spreadsheet allegedly containing personal information of Sony employees -- including several executives' salaries and the Social Security numbers of 3,803 employees -- leaked online. Fusion published portions of the spreadsheet on its website on Monday.
Sony was not immediately available for comment.
When Sony workers tried to log onto their computers last week, they were greeted with an image of a skeleton accompanied by the text "Hacked By #GOP."
The message, which contained multiple threats, appeared to be an attempt to blackmail Sony by a group calling itself Guardians of Peace. The attack resulted in the pirating of DVD copies of at least five movies, including Brad Pitt's "Fury" and the upcoming musical "Annie."
Some speculated that hackers in China working on behalf of North Korea could be responsible.
Staff writers Ryan Faughnder and Paresh Dave contributed to this report.