Here is a list of some write-ups I have done. I hope it will help you to get a better understanding of how to exploit vulnerabilities in the various field of information security.
DVWA - Damn Vulnerable Web Application
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is damn vulnerable. Its main goal is to be an aid for security professionals to test their skills and tools in a legal environment, help web developers better understand the processes of securing web applications and to aid both students & teachers to learn about web application security in a controlled class room environment.
You can access to the write-up with the following link: DVWA Write-Up.
Note: This write-up is constantly evolving. I will add solutions on the various levels as soon as possible.