Beware credit card skimmers

This guest post comes from David Weliver at Money Under 30 and is part of his series for National Protect Your Identity Week.

Talk about serendipitous. I've been planning a post on credit card and ATM skimmers -- jerry-rigged little devices criminals use to steal your card numbers -- and yesterday my brother tells me he spotted one of these suckers at a rest area on the New York Thruway.

He alerted managers, who called the cops, who confirmed it was a skimmer. It just proves that skimmers are a real threat out there. Skimmers give fraudsters easy access to unwitting victims' credit and debit card numbers -- even PINs. Here's what you need to know to avoid these nasty things.

How skimmers work

There are two big ways criminals use credit card skimmers to steal your information:

• They stealthily install a skimmer on an ATM or self-serve kiosk and capture your card information when you swipe your card. Sometimes the machine still works, and you never know anything is wrong. Sometimes the skimmer disables the machine, but you'll just assume it's out of order and move on.
• They get a hold of your credit card and skim your card manually (an easy racket for an unscrupulous waiter who could do this when you hand over your card to pay the bill).

Unless you catch your server in the act of swiping your card against his or her body -- they often keep skimmers hidden under clothing -- you probably won't know your card has been compromised this way until fraudulent charges appear on your statement. Fortunately, however, practicing a little vigilance can help you spot and avoid skimmers that are installed on self-service kiosks and ATMs.

Note from Karen: It's National Protect Your Identity Week, sponsored by the National Foundation for Credit Counseling and the Council of Better Business Bureaus. Here's some related reading that you'll find helpful.

·         Find 'shredding parties' in your state

·         Are you safe? 10 questions to find out

·         Steps to take if you've been victimized

·         Questions on identity theft? Ask an expert

How to spot skimmers

Credit card skimmers look just like the machines that merchants and ATMs use to legitimately swipe our plastic. Skimmers can come in all shapes and sizes. Some are so professional looking you might not be able to tell them apart from a real credit card machine; others (like the one my brother spotted) are sketchtastically homemade.

• Bing: What's an ID theft passport?

At ATMs or self-serve kiosks, high-quality skimmers may be attached on the outside of the legitimate card slot (so you put your card through both without realizing it). Lower-grade skimmers are attached in a location that's not the actual credit card slot and just rely on you to see the skimmer first and swipe your card through it. (Or the thieves may have disabled or covered up the legitimate card slot.)

One final note: Thieves who install skimmers on ATMs may also install a tiny camera that will attempt to record your PIN as you enter it. So it's a good habit to always cover the keypad with your free hand as you punch in your numbers.

Where can skimmers be found?

• Automated teller machines (ATMs).
• Gas pumps.
• Public transit ticket machines.
• Movie theater ticket kiosks.
• Red Box DVD rental machines.

What to do if you find a skimmer

If you suspect you've found a skimmer, call local police at once and notify the owners of the machine. If you fear you've used a skimmer, call your bank or credit card company and let them know. You and your bank can decide to cancel your card and replace it or simply keep an eye on your statement for any fraudulent activity.

Have you ever come across a skimmer? Have you had credit card details stolen by a skimmer? Please share your story. 

Related reading at Money Under 30:

• 7 signs you're at risk for identity theft
• Identity theft: What you need to know to protect yourself
• Identity theft growing in recession