The recent hack in the servers of JPMorgan Chase & Co exposed names, addresses, phone numbers and email addresses of the holders of some 83 million households and small business accounts, the bank revealed on Thursday. The bank revealed that the previously disclosed breach did not affect users's account numbers, passwords, user IDs, birth dates or Social Security numbers. It added that it has not seen "unusual customer fraud" related to the attack which exposed contact information for 76 million households and 7 million small businesses.

Still, JPMorgan advised customers on its website that it does not believe they need to change their passwords or account information.

At the end of August, JPMorgan said it was working with U.S. law enforcement authorities to investigate a possible cyber attack.