The information includes email addresses, mobile phone numbers and personal chat transcripts, according to a review by Bloomberg News on Friday. The data were leaked over the past weeks via a Twitter account called "G0d" that identifies itself as based in Hamburg and describes itself using the words "security researching," "artist" and "satire & irony."

It looks like the hackers got the passwords to Facebook accounts and Twitter profiles and worked their way up from there, said Simon Hegelich, a political scientist at Munich's Technical University who has studied the manipulation of social networks.

"It's a very elaborately done social engineering attack," he said Friday by phone. "It's a lot of data that's been dumped."