EDISON - If you’re one of the 40 million people who shopped at Target between Nov. 27 and Dec. 15, you may have had your credit or debit card information stolen in what could be the largest security breach in four years.

Target confirms someone hacked into its point-of-service computer system and stole customer names, card number, expiration dates and three-digit security codes. Target says online customers were not affected.

Paul Oster, a certified FICO professional who specializes in credit card fraud, says the hackers installed malicious software that redirected the “track data” collected during any in-store purchase using a card, and redirected it to the identity thieves. Credit card fraud is the fastest growing crime in the U.S., and Oster says even if you were not affected this time, sooner or later, almost everyone will fall victim to identity fraud of some kind.

So what should you do if you believe your credit card information was compromised? Kane In Your Corner offers this advice:

First, review your bank and credit card statements and check every transaction. If you see one that looks suspicious, notifiy your bank or credit card provider immediately. If you have online access to your statements, don’t wait for your monthly statement to arrive; instead, check at least once a week.

Also, check your credit report periodically to see if there are any new accounts set up in your name. You are allowed one free credit report a year from each of the three major credit reporting companies, and can obtain it by going to www.annualcreditreport.com.

You can also consider enrolling in a credit monitoring service, which will give you unlimited access to your credit report and will send you email or text alerts anytime something changes. Those services usually cost between $10 and $25 a month.

For an extra layer of protection, you can ask one of the credit reporting companies to issue either a credit alert or credit freeze. A credit alert warns businesses that you suspect someone may have gotten access to your credit information and asks them to use caution before issuing credit in your name. A credit freeze makes it impossible for anyone to issue new credit in your name unless you specifically authorize it using your individual password or PIN. Contacting one of the three credit reporting companies is sufficient as they are required by law to contact the other two.

Credit alerts and freezes have their drawbacks, however. A credit freeze will also make it impossible for you to get credit yourself, unless you remember to lift the freeze in advance. Credit alerts are not 100 percent reliable in stopping fraudulent behavior, and some consumers who have asked to have them issued have found they can lead to their own transactions being declined.

For more on the Target data breach click the video to the left or visit News 12 Extras on Optimum channel 612.