British service provider TalkTalk receives a ransom demand over cyber attack

London: TalkTalk said it had received a ransom demand from somebody claiming to be behind the cyber attack on the British broadband company on Wednesday, which involved the possible theft of the details of 4 million customers.

"It is hard for me to give you very much detail, but yes, we have been contacted by, I don't know whether it is an individual or a group, purporting to be the hacker," Chief Executive Dido Harding told the BBC on Friday.

Noting it was a live criminal investigation, she added: "All I can say is that I had personally received a contact from someone purporting - as I say I don't know whether they are or are not - to be the hacker looking for money."

Asked if the company would pay a ransom, a TalkTalk spokeswoman said the matter was in the hands of police.

The firm said late on Thursday that investigations were ongoing, but there was a chance names, addresses, dates of birth, phone numbers, email addresses, TalkTalk account details, credit card details and/or bank details were compromised.

"Potentially this could affect all of our customers. I don't know for certain, which is why we are taking the precaution of reaching out to everyone," CEO Dido Harding said.

The attack is potentially one of the biggest and most damaging to hit a British company, and comes after several high profile cases in North America. The details of millions of customers of infidelity website Ashley Madison were leaked in August after a massive cyber assault, while Sony Corp's film studios were hit in November 2014.

The attack is the third to hit TalkTalk this year, and experts said it would damage the reputation of the company, which competes with bigger rivals BT, Virgin Media and Sky.

The Metropolitan Police said its cyber crime unit was investigating an alleged data theft from a telecommunications website, without giving details.

Personal data including names, addresses and phone numbers were stolen from TalkTalk at the start of the year, and in August servers owned by Carphone Warehouse, the retailer which founded TalkTalk, were attacked, potentially affecting 480,000 TalkTalk mobile customers.

A spokeswoman said Wednesday's attack was the first time TalkTalk's own servers had been subjected to a sustained external attack.