Nessus : Vulnerability Scanner

Nessus : In computer security, Nessus is a proprietary comprehensive vulnerability scanning program. It is free of charge for personal use in a non-enterprise environment. Its goal is to detect potential vulnerabilities on the tested systems.

Nessus allows scans for the following types of vulnerabilities:

• Vulnerabilities that allow a remote hacker to control or access sensitive data on a system.
• Misconfiguration (e.g. open mail relay, missing patches, etc.).
• Default passwords, a few common passwords, and blank/absent passwords on some system accounts. Nessus can also call Hydra (an external tool) to launch a dictionary attack.
• Denials of service against the TCP/IP stack by using mangled packets
• Preparation for PCI DSS audits

first of all we need to Registerthe nessuss it will provide us the activation code. 

Go to the Application>Backtrack>Vulnerability Assessment>Vulnerability Scanners>Nessuss>Nessuss Registration.

It will send us on the nessuss website for registration click on home user register it will provide you a activation code 

Now follows the steps

Go to the terminal and type /opt/nessus/bin/nessus -fetch --register <Code here>

 Now we have to add a user for adding a user Go to Application>Backtrack>Vulnerability Assessment>Vulnerability Scanners>Nessuss>nessus user add 
or goto the terminal and type /opt/nessus/sbin/nessus-adduser

 To start the nessus goto Application>Backtrack>Vulnerability Assessment>Vulnerability Scanners>Nessuss>nessus start