WASHINGTON, March 30: Discount shoppers the world over were put on guard on Friday after the retail group TJX disclosed that some 45.6 million credit and debit card numbers were stolen by hackers in 2005 and 2006.

The company, which operates TJ Maxx and other stores in the United States and TK Maxx in Britain and Ireland, also said on Thursday some 455,000 customers may have had personal information compromised in the massive data breach.

The retailer made the disclosure in a filing with the Securities and Exchange Commission, expanding on its announcement earlier this year.

Avivah Litan, of the consulting firm Gartner Inc told the Boston Globe: “It’s the biggest card heist over. It’s done considerable damage.” The company said it learned on Dec 18, 2006 of “suspicious software” on its computer systems and later discovered “that there was strong reason to believe that our computer systems had been intruded upon.” The company subsequently notified law enforcement in the United States, Canada and Britain, and later determined that the intrusions may have dated back as far as July 2005.

Several lawsuits are pending relating to what some have described as the biggest financial data breach in history. Until now, the biggest data breach was the 2005 theft of 40 million credit cards numbers from the servers of the payment processor CardSystems Solutions.

According to US media, last week police arrested six people who had used credit card numbers stolen from TJX to rack up purchases of one million dollars.

In the second half of the year, Symantec found some six million computers were infected with suspect software.

A stolen credit card number, along with its security code, sells for between one and six dollars, the company said. More complete personal information, including a bank account number, date of birth and social security number sells for between $14 and $18, according to Symantec.—AFP