It's the latest in a series of attacks which have hammered the electronics multinational. Security researchers have counted about a dozen breaches since the beginning of this year, including two particularly serious ones which exposed 100 millions users' personal details.
The latest attack was claimed by "Idahc," who self-identifies as a Lebanese hacker. The Associated Press has been able to verify several of the exposed names.
A U.S.-based spokeswoman for Sony Corp. has not returned an email seeking comment.
The website allegedly hacked into was down for "scheduled maintenance" Saturday.