The Sun newspaper's website has been the target of a hacker with News International warning that the hacker may have posted users' names and addresses online.
The news follows the recent attack on The Sun's site last month from hacking group LulzSec, in which the group posted a fake story claiming Rupert Murdoch had died from a drug overdose.
The hacker who claims responsibility for posting details of registered Sun website users calls himself Batteye on Twitter and is said not to be linked to LulzSec.
News International has responded by emailing hundreds of thousands of users to warn them that their personal details may have been compromised if they have recently entered a competition or taken part in a poll on The Sun's website.
The news could not come at a worse time for News International, following the ongoing investigations into accusations of phone hacking at the (now defunct) News of the World newspaper.
Director of customer data for News International, Chris Duncan, said, "Some customer information from competitions and polls was breached" – including readers' names, addresses, dates of birth, emails and phone numbers.
"No financial or password information was compromised," Duncan adds.
Duncan also says News International is working closely with the police and the information commissioner "to ensure that all steps are taken to retrieve the files involved".
The hacker writes on Pastebin, "We will begin today be presenting to you, various files obtained from the Sun, a company within the News Corp group. We will continue, then, by exposing the world for what it is; a less than perfect place where we cannot trust those who we ask to protect our information."
Via The Guardian