What type of scanner is Nessus classified as within the ACAS framework?

Nessus is classified as an active scanner within the ACAS framework. Active scanners are designed to actively probe and interact with systems on a network to identify vulnerabilities and security weaknesses. This type of scanning involves sending requests to target systems and analyzing their responses to gather information about potential security issues.

The active nature of Nessus allows it to conduct thorough assessments by performing detailed checks for vulnerabilities, misconfigurations, and compliance with security policies. This is essential for organizations aiming to assess their security posture accurately and proactively address any vulnerabilities discovered.

In comparison, passive scanning involves monitoring network traffic without sending requests, which does not provide the same level of data about system vulnerabilities. A hybrid scanner combines elements of both active and passive scanning, while a network scanner is a broader category that may refer to tools that scan for a variety of devices and services. Thus, classifying Nessus as an active scanner captures its operational focus on engaging with systems to uncover vulnerabilities effectively.