East Coast supermarket chain hit by data breach; 4.2 million account numbers affected

Hannaford Bros., a supermarket chain with stores primarily in the Northeast and Florida, said Monday that it was hit by a data breach that exposed 4.2 million credit and debit card numbers.

Overall, 1,800 case of fraud have been reported due to the breach. The company said no personal data was released. In an FAQ and letter from the chain's CEO, the company said that it became aware of the breach Feb. 27. The breach began Dec. 7, but wasn't contained until March 10, according to reports.

The company said the account numbers were "illegally accessed from Hannaford’s computer systems during the card verification transmission process in transactions." Hannford added that it now has "comprehensive data security systems in place" that go beyond industry standards.

The Massachusetts Bankers Association also issued a statement on the incident.