Citibank is re-issuing a number of MasterCard credit and debit cards used in the UK, Canada and Russia, after admitting customer accounts have become compromised after its network was breached.
The bank said it had become aware of a “third-party business information breach”. It would not be more specific, but this could mean that a retailer or credit clearing house had lost customers’ data.
Citibank said that last month it had detected “several hundred fraudulent cash withdrawals in three countries”.
As a result, said the bank, it was re-issuing cards to those customers affected. It said it had already blocked PIN-based transactions on some of the cards that have been compromised, preventing any ATM withdrawals.
The Bank of America recently reported its second major data breach in a year. The largest US bank cancelled the debit cards of a number of its customers following a data security breach at an undisclosed company. It is not clear whether the breach affected an online company or a high street chain.
The bank did not disclose the number of customers affected, but it said many would have their cards cancelled and replaced as a precaution.