In the first edition of this critically acclaimed book, Andrew Hoffman defined the three pillars of application security: reconnaissance, offense, and defense. In this revised and updated second edition, he examines dozens of related topics, from the latest types of attacks and mitigations to threat modeling, the secure software development lifecycle (SSDL/SDLC), and more. Hoffman, senior staff security engineer at Ripple, also provides information regarding exploits and mitigations for several additional web application technologies such as GraphQL, cloud-based deployments, content delivery networks (CDN) and server-side rendering (SSR). Following the curriculum from the first book, this second edition is split into three distinct pillars comprising three separate skill sets: Pillar 1: Recon-Learn techniques for mapping and documenting web applications remotely, including procedures for working with web applications Pillar 2: Offense-Explore methods for attacking web applications using a number of highly effective exploits that have been proven by the best hackers in the world. These skills are valuable when used alongside the skills from Pillar 3. Pillar 3: Defense-Build on skills acquired in the first two parts to construct effective and long-lived mitigations for each of the attacks described in Pillar 2.