When the world’s largest online retailer allows anyone and everyone to list products for sale without requiring proof of inventory or legitimacy there’s always going to be a handful of bad seeds. In the past couple of months, however, instances of Amazon third-party seller fraud have absolutely exploded, and thanks to leaked login credentials of reputable sellers, it’s now harder to detect than ever.

If you’ve visited the Amazon listing for the Nintendo Switch in recent weeks you’ve probably noticed the huge number of third-party sellers with listings for “Brand New” merchandise at prices well below actual retail. Being the intelligent individual that you are, you know when something is too good to be true and avoided the tempting deal entirely, but not everyone is so skeptical, and lots and lots of people have fallen victim to third-party seller fraud. It’s always been a problem on Amazon, but with so many username and password leaks from other sites and services out there, sketchy sellers have begun commandeering the accounts of real, but inactive, sellers and using their good names and positive ratings to con buyers.

Amazon is attempting to crack down on the troubling trend, but it can be hard to spot in some cases. Many of the fake listings, which can be up to $100 or more below retail price for any given item, sometimes come from accounts with 4- and 5-star ratings and long histories of positive transactions. The hacker, using stolen credentials, takes over the account and changes banking information, then places the phony listings, cashing out even before the buyer realizes they’ve been conned.

As the Wall Street Journal reports, not all of the hacked accounts are dormant ones, and some active sellers have seen their profiles and profits taken over by fraudsters who withdraw their hard-earned cash to brand new accounts before the account holder has time to react.

So if you’re shopping for ridiculously good deals on Amazon, be sure to double-check both the seller’s info and your own common sense before swiping your digital credit card.

Amazon has provided the following statement on the matter:

“We want customers to buy with confidence anytime they make a purchase on Amazon.com. With the A-to-z Guarantee, customers are always protected whether they make a purchase from Amazon or a third-party seller. If ever the product doesn’t arrive or isn’t as advertised, customers can contact customer support for a full refund of their order. Amazon has zero tolerance for fraud. We withhold payment to sellers until we are confident that our customers have received the products and services they ordered. In the event that sellers do not comply with the terms and conditions they’ve agreed to, we work quickly to take action on behalf of customers. There have always been bad actors in the world; however, as fraudsters get smarter so do we. Amazon is constantly innovating on behalf of customers and sellers to ensure their information is secure and that they can buy and sell with confidence on Amazon.com. There are several steps sellers can take to protect their accounts, including monitoring their account on a frequent basis, updating their password regularly and by using two-factor authentication. If anything looks suspicious, sellers should reach out to Amazon immediately so we can investigate by contacting Seller Support via our urgent help feature in Seller Central. For more best practices, sellers can visit: https://www.amazon.com/gp/help/customer/display.html?nodeId=13832211#security”