Forum Thread: How Do I Extract Data from a Website

That is a pretty generic question. There isn't any simple, nor single answer that would suffice. I would suggest that you start reading and learning first, so that you understand what you are doing and why you are doing it. A good place to start would be right here on this site.

If you want my opinion, I would start with the basics. There isn't any magical method to gain access. There are so many ways that may accomplish your goal (e.g. SQL Injection, exploitation of a vulnerable service, exploit an OS vulnerability, heck you may be able to simply alter the HTML form data and reset a password for a known user if the website offers that functionality). The point is that you must understand the basics before you can even begin to know what you can do.

That being said, if you are looking at concentrating on web applications and servers, OWASP offers an extensive amount of information with actual step-by-step instructions for testing different known vulnerabilities. In addition, they used to offer a vulnerable web application called Webgoat that allows you to practice. There are, as some of the posts here have pointed out, vulnerable and old versions of different operating systems that can be downloaded and used for practice. Set up a test lab (there are posts here on doing that). This is a great site to learn. Remember, the people here that are great at what do they do have invested the time; it takes lots of practice, they didn't get their knowledge over night.

My two cents anyway...

:-)