We are going to be learning about a popular type of vulnerability called SQLi. Before we discuss how it occurs and how to exploit it, let's first learn what SQL is. For example, if we are performing a pen test on a certain website, the chances are the website is a little bit bigger than other websites and so probably uses a database. Most websites, other than very simple ones use databases to store data, such as usernames, passwords, news articles, blog posts, pictures, and anything that happens on the website. The web application reads the database and then displays the data to us or to the users. When the user performs an action on the website, the application will either update, delete, or modify the data that exists in the database. This interaction between the web application and the database happens using a language called SQL.
Let's see what we mean...