Albany, NY (AHN) - Hannaford Bros. Co, a supermarket chain based in Maine, said data from 4.2 million credit and debit cards was stolen in a scam run between Dec. 7 and March 14. The ruse allowed unknown hackers to steal information as customers swiped card during checkouts.

First reported by The Boston Globe, the company said it was unaware how the malware got into the scanners linked to banks for store purchases approval. In a statement, the company said it knows of 1,800 cases of fraud resulting from the stolen credit information.

A class-action lawsuit was filed Wednesday on behalf of an Albany, NY customer of the supermarket chain. The legal action asks Hannaford to pay for credit monitoring and legal fees. Hannaford CEO Ronald Hodge has told customers some should expect "extraordinary out-of-pocket expenses" related to dealing with the data loss. In a letter, Hodge said the company would deal with those expenses on a "case-by-case basis," the Albany Times-Union reported Friday.