Magento, checking core files for credit card skimming

Hey guys,

Does anyone know what core files a hacker (using a web shell) would need to modify in Magento in order to skim credit card information from the checkout process?

So far the only file I can see that would allow this is core/Mage/Checkout/controllers/OnepageController.php but I just want to make sure there's nothing else.
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Eddie ShipmanAll-around developerCommented:
It would most likely be the payment processor code. If you're using Paypal, check the app\code\core\Mage\Paypal\ files.

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