El objetivo de este libro es introducir al lector en el mundo del pentesting web o hacking de páginas y aplicaciones web. (Description in English below). Se centra en la seguridad de páginas web y el modo de mejorar los niveles de seguridad. Además, podrás conocer las diferentes técnicas de ataque de manera guiada contra aplicaciones web, así como las contramedidas para proteger tus recursos. Desprintion in The objective of this book is to introduce readers to the world of Web Pentesting or Hacking of Pages and Web Applications. In it, you will be able to know the different attack techniques in a guided way against Web applications, as well as the recommended countermeasures to protect your resources from this type of attack. Web pages and applications are one of the technologies in the IT world with the highest growth over time. The famous trend of bringing all services to the Web world. It has gone from a small number of Web portals available in the past, to a total presence of all kinds of companies on the Internet, being, today, one of the means of communication capable of providing more effective services between companies and customers. For this reason, this book focuses on the security of this type of Web applications and how to improve security levels. Where the best way to understand your security is to know how attacks are carried out and how their vulnerabilities are exploited.