Magecart came to light in 2018, where various groups of attackers siphoned credit card data from thousands of e-commerce implementations across the globe. This talk will focus on how and where these attacks occur as well as the various defensive strategies that can be used to prevent them. The discussion will be relatively high-level, but there will be a dash of JavaScript and a detailed technical breakdown of Content Security Policy (CSP) and Subresource Integrity (SRI), both of which are critical for defense.