Target Customers Had Credit Card Info Stolen On Black Friday: Report.......40 Millions may be affected.

Dec 18 (Reuters) - An unknown number of Target Corp customers shopping over the busy Black Friday weekend had their credit card information stolen in an "extensive" breach of the U.S. retailer's security, Dow Jones reported on Wednesday, citing people familiar with the matter.

The theft may have occurred through software installed at machines customers use to swipe their cards when paying, Dow Jones cited one of the unidentified sources as saying.

The Black Friday weekend after Thanksgiving is among the busiest shopping periods of the year. Target did not respond to requests for comment.