'Extensive Security Breach' Alleged At Target Stores Nationwide

LOS ANGELES (CBSLA.com) — Federal investigators are looking into what is being called an "extensive" security breach involving Target stores nationwide.

The breach could affect millions of shoppers.

Crystal Cruz, reporting for KCAL9/CBS2, spoke to many consumers in Moreno Valley Wednesday who didn't know about the breach.

The Secret Service told Cruz "a major investigation" was underway but refused to say any more than that.

The Wall Street Journal reported that shoppers who used their credit or debit cards on Black Friday -- and since -- are most likely affected.

Cruz spoke to shoppers who said they didn't receive notice from the store, that they didn't see any signage inside or outside the store alerting consumers to the alleged hacking.

"So you're in the dark?," she asked one Target customer who simply replied, "Yes."

According to the Wall Street Journal, card reading machines may have been tampered with and that's how valuable credit and debit card data could've been stolen.

Experts on consumer fraud say that stolen data, in turn, can be used to issue fake cards.

Seth Rosenblatt, with CNET.com, explained why the Secret Service is now investigating.

"The Secret Service would probably be investigating if there was an international component to this," said Rosenblatt.

"This is one of those situations where in the past its been done by hacking into stores wifi and using that to get into a stores corporate data base. Again we don't know yet how this happened," Rosenblatt added.

This news caused some Target shoppers to use alternate forms of payment Wednesday night.

"I have other options so I think I might take that up," said Fran Jorgenson.

Cruz said Target could not be reached for comment.