US investment bank JP Morgan (NYSE:JPM) has revealed the size of the security breach it suffered earlier this year was one of the largest in history.
The bank confirmed that a cyber-attack, which started in June and went unnoticed for a couple of months, gained access to the accounts of 76mln private customers and about seven million small businesses.
The bank reassured clients that there is no evidence that financial information was compromised.
The attacker downloaded details such as names, addresses (including email addresses), and phone numbers, but not critical information such as login identities, passwords, account numbers or social security codes.
The banking giant said it has yet to see “any unusual customer fraud related to this incident."
JP Morgan Chase has been working with the Federal Bureau of Investigation (FBI) and US intelligence officials to investigate the attack, which some news agencies have suggested was perpetrated by Russian criminals.
A similarly successful attack was made recently on retail giant Home Depot (NYSE:HD), while earlier in the year the chief executive of retailer Target (NYSE:TGT) walked the plank after the company’s information technology system was breached.