Nessus Components
Before we start our first vulnerability scan with Nessus,
we’ll take some time to get familiar with the core components.
First, let’s investigate the tabs in the Nessus dashboard.
In the Essentials version of Nessus, we have two tabs called Scans and Settings.
The Settings tab allows us to configure the application.
For example,
we can enter information for an SMTP server to get scan results via email.
The advanced menu allows us to configure global settings
ranging from user interface,
scan and log behavior, to security and performance related options.
The About menu lists basic information for Nessus, our license,
and how many hosts we have left.
For further information on how we can customize and configure Nessus,
we can review the Nessus documentation.
Next, let’s examine policies and templates,
we’ll click on the Scan tab then on Policies.
A policy is a set of predefined configuration options
in the context of a Nessus scan.
When we save a policy, we can use it as a template for a new scan.
Let’s now click on Scan Templates.
Nessus already provides a broad variety of scanning templates for us to use.
These templates are grouped into the three categories Discovery, Vulnerabilities,
and Compliance.
The Compliance category is only available in the enterprise version,
as well as the Mobile Device Scan template.
The only template in the Discovery category is Host Discovery,
which can be used to create a list of live hosts and their open ports.
The Vulnerabilities category consists of templates for critical vulnerabilities
or vulnerability groups such as, PrintNightmare or Zerologon
as well as templates for common scanning areas
like Web Application Tests or Malware Scans.
Nessus also provides three general vulnerability scanning templates:
The Basic Network Scan
performs a full scan with the majority of settings predefined.
It will detect a broad variety of vulnerabilities
and is therefore the recommended scanning template by Nessus.
We also have the option to customize these settings and recommendations.
The Advanced Scan is a template without any predefined settings.
We can use this when we want to fully customize our vulnerability scan
or if we have specific needs.
The last general scanning template, Advanced Dynamic Scan,
also comes without any predefined settings or recommendations.
The biggest difference between the two templates
is that in the Advanced Dynamic Scan, we don’t need to select plugins manually.
The template allows us to configure a dynamic plugin filter instead.
Nessus Plugins are programs written in the Nessus Attack Scripting Language (NASL)
that contain the information and the algorithm to detect vulnerabilities.
Each plugin is assigned to a plugin family which covers different use cases.
We will work with the Advanced Dynamic Scan template
and plugins in the last section of this Learning Unit.