Virtually all small businesses today must accept credit card payments, and with the growth of e-commerce, accepting online payments has increasingly become a must do. Unfortunately, this means small businesses must expose themselves to the multi-billion dollar industry of credit-card processing fraud.
Thankfully, there are basic steps small businesses can take to minimize their vulnerability. Here’s how you can minimize the risk of being a victim of e-commerce credit-card processing fraud:
1. Limit failed transactions.

There is a robust online market for stolen credit cards on the dark web. Fraudsters will buy credit cards by the dozens and use them to purchase e-commerce merchandise–especially from small businesses because smaller companies have fewer protections than larger business.

Thankfully, fraudsters who use stolen credit cards are often sloppy or have incomplete information about the victim cardholders. As a consequence, they often use software to guess at things like .cardholders’ zip code or Security code, and with a payment gateway that isn’t properly configured, they can guess thousands of times via software, until they guess the right answer.

By simply limiting the number of failed transactions that process through the payment gateway before a card is completely blocked, you effectively limit the number of “bad guesses” that a fraudster can do. Generally, setting the number at two to three failed attempts is sufficient to ensure that legitimate customers can fix a typo, while also being a low enough number to ensnare most fraudsters attempting to guess at cardholder information.
2. Limit damage by flagging large transaction sizes.

Source:http://www.pajontech.com/2016/06/how-to-prevent-credit-card-processing.html