Target hackers first broke into the retailer's system by using network credentials stolen from Fazio Mechanical Services, a refrigeration and HVAC systems provider, sources told security news and investigation website KrebsonSecurity.com.
Last week, Target said that the initial intrusion into its systems was traced back to network credentials that were stolen from a third-party vendor.
According to Fazio Mechanical's website, the company has also has done refrigeration and HVAC projects for specific Trader Joe's, Whole Foods and BJ's Wholesale Club locations in Pennsylvania, Maryland, Ohio, Virginia and West Virginia.
Click here to read the full story from Krebs on Security.
–By CNBC.com
