'Biggest data leak ever' hits Japanese ISP

The biggest data leak ever has officially hit the internet, with the details of more than 4.5 million bank customers exposed.

Japan's largest broadband service provider, Softbank BB, suffered the customer database leak last month. The company said that 4.52 million user details, including names, phone numbers, addresses and email IDs - but no passwords or credit-card details - were exposed, in what is thought to be part of an extortion attempt.

Tokyo police have arrested several suspects, with one 'man on the inside', Hiroshi Mori, alleged to have copied and passed on the data to the extortionists, who were threatening to publish the data online unless they received they received billions of yen.

It looks like Softbank will be taking a severe hit to the company purse in any case - the broadband company will be paying out several billion yen to compensate customers for the leak. It looks like the company's call centre will also be needing a cash injection, with nearly 2,000 customers calling up in the wake of the leak.

The company is currently investigating and said in a statement that it will be tightening "internal restrictions on access to client data and strengthening surveillance systems to monitor unauthorised access [as well as] upgrading compliance procedures throughout its operations, including subcontractors."

While it's not yet known if any of the past and present customers listed on the database have been affected as a result, one man who will be worse off is Softbank's CEO, Masayoshi Son, who will be taking a 50 per cent pay cut for six months as a result of the leak.