Linux Basics for Hackers

Starting, Stopping, and Restarting Services

Before we begin to work with these four crucial services, let’s start by examining how to start, stop, and restart services in Linux.
Some services can be stopped and started via the GUI in Kali Linux, much as you would on an operating system like Windows or Mac. However, some services require use of the command line, which we’ll look at here. Here is the basic syntax for managing services:

service servicename start|stop|restart

To start the apache2 service (web server or HTTP service), you would enter the following:

kali >service apache2 start

To stop the Apache web server, enter:

kali >service apache2 stop

Usually, when you make a configuration change to an application or service by altering its plaintext configuration file, you need to restart the service to capture the new configuration. Thus, you would enter the following:

kali >service apache2 restart

Now that you understand how to start, stop, and restart services from the command line, let’s move on to the four most critical Linux services to hackers.

Creating an HTTP Web Server with the Apache Web Server

The Apache Web Server is probably the most commonly used service on Linux systems. Apache is found on over 60 percent of the world’s web servers, so any self-respecting Linux admin should be familiar with it. As a hacker aspiring to hack websites, it’s critical to understand the inner workings of Apache, websites, and the backend databases of these sites. You can also use Apache to set up your own web server, from which you could serve up malware via cross-site scripting (XSS) to anyone who visits your site, or you could clone a website and redirect traffic to your site via abuse of the Domain Name System (DNS). In either of these cases, a basic knowledge of Apache is required.