American Express is notifying around 77,000 California customers that their personal information and card data has been posted on various websites by members of the hacktivist group Anonymous Ukraine.
In March 2014 the Ukrainian arm of the Anonymous collective posted 3,255,663 records from Visa; 1,778,749 records from MasterCard; 362,132 record from Discover; and 668,279 records from American Express, as reported by csoonline.com.
Informing to the California OAG, the financial firm said that it will dispatch letters to more than 58,000 residents through the US Postal Service about the data theft incident.
While the fraud threat is considered minimal, AmEx has now moved to warn affected customers. As picked up by CSO, the firm has written to the California Attorney General’s Office about its decision.
AmEx is writing to 58,522 Californians whose names and corresponding account numbers were involved, as well as another 18,086 whose card information was published but not their names.
The letter that will be send out to the cardholders reads, "We were recently made aware that your American Express Card information was recovered during an investigation by law enforcement and/or American Express."
"At this time, we believe the recovered data may include your American Express Card account number, the card expiration date, the date your card became effective and the four digit code printed on the front of your card."
Assuring its customers, the card company said that the social security numbers were not hacked and no fraud has been detected on the affected cards.
In addition, AmEx said it has placed additional fraud monitoring on the individual’s account, and that they will not be held liable for any fraudulent charges.