WVLT- Target is doing damage control after 40 million credit and debit card accounts were affected by a data breach.
No one is saying for sure, but Target says it's not online and a security expert says this may have been an issue with the point of sale machines.
John McNeely, President and CEO of Sword and Shield Enterprise Security works with different retailers everyday,
"Where the card was swiped, there's some compromise there, or there's something further into the Target card processing environment."
Target says the accounts were impacted between November 27th and December 15th.
"The timing of this, this is the biggest shopping season of the year, that's not a coincidence and the scale of this being nation wide and it being very organized, I wouldn't be surprised if this was an inside job," says McNeely.
The Secret Service is investigating who is behind this, but it's making more people aware.
McNeely says that's important for shoppers pay close attention to their bank statements.
"You want to be on top of that and be diligent and if you've seen any suspicious activity you want to report it to your bank immediately," he says.
Target has more than 1600 stores here in the US and 124 in Canada.
Target says they've resolved the issue.
If you see any suspicious activity call your bank to report it and Target says to call 866-852-8680 so they know as well.