We are currently setup using Magento on a LAMP stack for our e-commerce platform. As of a month or two ago we began noticing a lot of carding attempts against our website. All attempted transactions would be for a small amount, just to check if their credit card is valid. As one is declined they usually try it again repeatedly changing the card number by 1 or 2 numbers. These attempts happen very quickly, in succession. As you can imagine, this adds up quickly in our credit card processors system and often times we get shut down for a brief period of time to prevent more attempts.
Most of the attacks were coming from outside of the U.S. and we are a U.S. only business so we used mod_geoip to deny all traffic from outside of the country. This has helped with the mass attacks but we still get people carding from U.S. origins. I am really interested in knowing what’s going on here. How do they setup scripts to mass attempts orders like this? Is there really anything else I can do to stomp this out? Any insight on these types of attacks is appreciated!