Nessus is a powerful fingerprinting tool. It can be used to find vulnerabilities in a target's machine. After finding vulnerabilities you may exploit them by searching for exploits online, using Metasploit, or Coding your own. I will be going over each one in this tutorial.

Part 1 - Installing
To install Nessus, you need the Nessus client and the server. Preform this command:

This will install both Nessus and Nessusd(The nessus server). Now run nessusd, set it up and keep the server running while using the Nessus client.
To run the Nessus server, just type "nessusd". Now type "nessus" to run nessus client. It should open a GUI of nessus. From here, just update Nessus and download new plugins.

Part 2 - Finding a vuln
Now we use Nessus to find a remote vulnerability on the target system. To do this, type your nessud username and password in the Username and Password fields. For the field titled "Nessud host" type "localhost" now for the port type the nessusd port(Default:1241)
Now hit login. After a few seconds you should be logged in. Now hit the "Target" tab on the top. From here you can make a .txt file with all the hosts to scan. For this scan, we are going to scan one host on our network, 192.168.1.8
So type that in the "Target(s)" box. Check the "Save this session" box, to save this session for later use. Now hit the "Start the scan" button. This will start a vulnerability scan on the target. So now I wait, and I wait, and I wait. After a bit Nessus should show the vulns. So we see that this box is vulnerable to a certain Microsoft RPC remote code execution vulnerability at high risk. Save the scan to a .xml file, which will be used for Metasploit and future archiving.

Part 3 - Exploitation(Find online)
So now we know what our target is vulnerable to. Try these sites:
http://exploit-db.com/
http://milw0rm.com/

So from here we can search for exploits. Lets say we find a .pl exploit for this vulnerability. We save it to a .pl file, and type this:

This will execute the Perl exploit

Part 4 - Exploitation(Metasploit)
Now we will use Metasploit to exploit the target. We know what it's vulnerable to, and we know Metasploit has a exploit module for this. Open Metasploit and type

After a bit, all the exploits Metasploit has to offer will be shown. So for this exploit we will use

To use this exploit type

This will load this exploit module and it should look like this:

Now we are using that exploit. Now type

This will show all available payloads you can use with this exploit. Find one that you want to use. We will be gaining a Meterpereter session, so we type this:

This will use reverse TCP meterpreter session. Now we use this command:

This will show the options available for this. We're going to set the RHOST to 192.168.1.8 by using the command:

Now this sets RHOST to 192.168.1.8 Now type show options again, make sure everything is set to how you want and type the following:

This will simply exploit the target machine. After a couple seconds you should get a meterpreter session!

Part 5 - Coding your exploits
One essential part of hacking is coding. I recommend starting with Python, then C, then ASM and then whatever languages you want. If we wanted to code an exploit in Python, we need to know how the vulnerability works, etc.. We also must learn how to code Sockets. Sockets are essential. This will be what we're using to connect to the target machine, and send the payload. The payload is usually Shellcode, but can be other things.

I hope you enjoyed this short tutorial on finding vulnerabilities with Nessus and exploiting them.

--Chroniccommand