Supermarket data breach affects 4.2 million accounts

The Hannaford Bros. supermarket chain said a breach of its computer system potentially exposed about 4.2 million credit and debit card numbers from its Hannaford and Sweetbay stores and other locations.

Hannaford, based in Maine, said about 1,800 cases of fraud have been tied to the breach, but no personal information -- such as names or addresses -- was accessed, and it has contained the breach. The security lapse is the latest to affect a large retailer, and comes amid tougher scrutiny on the payments industry following a breach that emerged last year that compromised as many as 100 million card numbers of customers of Framingham retailer TJX Cos.

Hannaford operates 165 stores in the Northeast. There are 106 Sweetbay supermarkets in Florida. The company said in a statement posted to its website that the stolen data was "illegally accessed from our computer systems during transmission of card authorization.''

Separately, the Massachusetts Bankers Association said today that Visa and MasterCard had warned as many as 70 banks in Massachusetts about a large data breach at a major retailer, and association urged consumers to monitor their accounts.

The banking trade group said neither Visa nor MasterCard would identify the source of the breach.
(By Ross Kerber, Globe staff)

Material from Globe wire services was used in this report.