Citigroup's Japanese credit card unit said personal information for more than 92,000 of its customers was illegally sold to a third party.
The information exposed included the names, account numbers addresses, phone numbers birthdates, and sex of 92,408 credit card holders, Citi Cards Japan warned in an advisory (PDF) issued Friday. The personal identification numbers and card security codes were not accessed.
Friday's warning is at least the second time in two months Citigroup has admitted to a security breach that compromised its customers' privacy. In June, Citigroup said a hack attack that exploited a garden-variety web flaw exposed personal information for more than 360,000 accounts and generated $2.7 million in losses for the banking giant.
Citi Card Japan didn't say how the information fell into the hands of outsiders, but according to The Japan Times: “A person involved in a company to which Citi Cards outsourced part of its business illicitly obtained the information and sold it to a third party, the unit of Citigroup said Friday.”
Citi Cards Japan said Friday it has seen no evidence of unusual or suspicious credit card transactions relating to the theft and that it has placed internal fraud alerts and enhanced monitoring on all affected accounts. It is fully cooperating with authorities investigating the breach. ®