Stolen credit card data is being used by fraudsters to make big purchases via Apple's popular mobile payment system, according to reports.

A majority of the purchases made by criminals using Apple Pay were at the tech giant's own stores, seeing as products there have a higher resale value, according to The Wall Street Journal.

Additionally, some of the stolen credit card data being used comes from the Target and Home Depot breaches. Since the Apple Pay system leaves card verifying process up to the banks, Apple Pay itself has not been compromised, rather, cybercriminals have found holes in their verification process to ultimately leverage the system to purchase goods.

Thanks to the “low-tech” means of identifying those vulnerabilities, banks are stepping up their payment verification efforts when it comes to Apple Pay.