Card-skimming is the illegal copying of information from the magnetic strip of ATM cards for the purpose of
stealing the money from your bank. The scammers try to steal your details so they can access your accounts. Once
scammers have skimmed your card, they can create a fake or ‘cloned’ card with your details on it. The
scammer is then able to run up charges on your account.
Card Skimming is accomplished through methods as low-tech as simply watching over your shoulder as you use the ATM
or as high-tech as installing false card readers (or whole false fronts) on top of existing ATM's.
- A shop assistant takes your card out of your sight in order to process your transaction
- You are asked to swipe your card through more than one machine
- You see a shop assistant swipe the card through a different machine than the one you used
- You notice something suspicious about the card slot on an ATM (e.g. an attached device)
- You notice unusual or unauthorized transactions on your account or credit card statement
Here is a good link and video explaining how the process works.