Citibank has imposed transaction blocks on an unspecified number of US card accounts after suffering a series of fraudulent cash withdrawals at ATMS in the UK, Russia and Canada.
News of the security scare spread like wildfire over the Internet after a Citibank customer reported the problems in a blog update. An apparent media blackout by the US bank fanned the flames, leading to wild speculation in the blogosphere that the bank's global ATM network had been compromised.
Citi has since issued a statement in an attempt to clarify the position, indicating that the security problems stem from a previous breach at a US retailer.
"Recently, we became aware of fraudulent ATM cash withdrawls on Citi-branded MasterCard credit and debit cards used in three countries on customer accounts that had been possibly compromised in previous retailer breaches in the US," says the bank in its prepared satement. "To protect customer accounts that were affected, we placed a special transaction block in those three countries on PIN based transactions. We are currently reissuing cards, as appropriate, to affected customers."
The bank has yet to identify the afflicted retailer or quantify the number of customer card accounts affected. A spokesman in the UK says the breach happened "some time ago", and that the problem is limited to an unspecified number of US cardholders. He says cards are being re-issued to affected customers "as appropriate".