What is a Magecart skimmer?

Magecart is the most common card-stealing attack on Magento. The attacker injects a small piece of JavaScript into your checkout that silently copies customers’ credit-card details as they type, then sends them to a server the attacker controls. It can hide in checkout JS, a CMS block, layout XML, a third-party script, or directly in the database. Because it doesn’t change how the page looks, stores often run infected for months. Magecart removal is a core part of every cleanup we do.