A massive campaign impacting nearly 100 online stores using the Magento e-commerce platform hides credit card-stealing code in a pixel-sized Scalable Vector Graphics (SVG) image.

When clicking the checkout button, the victim is shown a convincing overlay that can validate card details and billing data.

The campaign was discovered by eCommerce security company Sansec, whose researchers believe that the attacker likely gained access by exploiting the PolyShell vulnerability disclosed in mid-March.