TalkTalk says cyber attack affected 4% of customers

TalkTalk said on Friday that the cyber attack it suffered in October was a lot smaller than it originally suspected.

The telecommunications company said 4% of its customers have sensitive or personal data at risk.

TalkTalk said a total of 156,959 customers’ bank details were accessed, of which 15,656 bank account numbers and sort codes were seen.

In addition, it said the 28,000 obscured credit and debit card numbers that were accessed cannot be used for financial transactions and were ‘orphaned’, meaning customers cannot be identified by the stolen data.

Nevertheless, the company advised customers to remain vigilant and take precautions to protect themselves from scam phone calls and emails.

“It was a difficult decision to notify all our customers of the risk before we could establish the real extent of any data loss. We believe we had a responsibility to warn customers ahead of having the clarity we are finally able to give today,” said TalkTalk.

Earlier this week, a fourth person was arrested in connection with the TalkTalk hack.

The Metropolitan Police arrested a 16-year old boy at an address in Norwich on Tuesday evening on suspicion of Computer Misuse Act offences. This followed the arrest of a 20-year old man from Staffordshire on Saturday, a 16-year old boy in Feltham last Thursday and a 15-year old boy in Country Antrim, North Ireland, last Monday.

They have all been released on bail pending further enquiries.

At 0837 GMT, shares were up 5.6% at 233.29p.