Supermarket chain Hannaford Bros. is spending millions of dollars to upgrade its security in a bid to close the holes that allowed thieves to steal up to 4.2 million credit and debit card numbers from store networks. The remarkable thing about this case is not that the company was hacked, despite being certified as compliant with the security rules laid out by the payment card industry, but that so few retailers and businesses who accept card data even reach the level of security Hannaford had in place prior to its breach. In a conference call with reporters Monday, Hannaford chief information officer Bill Homa said the company planned to spend millions of dollars putting “military- and industrial-strength” security controls in place at its corporate and store networks. To that end, Homa said Hannaford is installing new intrusion-prevention systems to monitor the company’s various networks, and that it is in the