Nessus - Write-up - TryHackMe



  • Name: Nessus
  • Profile:
  • Difficulty: Easy
  • Description: Part of the Red Primer series, learn how to set up and use Nessus




Install tools used in this WU on BlackArch Linux:

pikaur -S nessus

Disclaimer: answers are very easy, obvious, given in the question or the description or just requires to search the help page so I won't give details here.

[Task 3] Nessus Quiz#


As we log into Nessus, we are greeted with a button to launch a scan, what is the name of this button?

Answer: new scan


Nessus allows us to create custom templates that can be used during the scan selection as additional scan types, what is the name of the menu where we can set these?

Answer: Policies


Nessus also allows us to change plugin properties such as hiding them or changing their severity, what menu allows us to change this?

Answer: Plugin Rules


Nessus can also be run through multiple 'Scanners' where multiple installations can work together to complete scans or run scans on remote networks, what menu allows us to see all of these installations?

Answer: Scanners


Let's move onto the scan types, what scan allows us to see simply what hosts are 'alive'?

Answer: Host Discovery


One of the most useful scan types, which is considered to be 'suitable for any host'?

Answer: Basic Network Scan


Following a few basic scans, it's often useful to run a scan wherein the scanner can authenticate to systems and evaluate their patching level. What scan allows you to do this?

Answer: Credentialed Patch Audit


When performing Web App tests it's often useful to run which scan? This can be incredibly useful when also using nitko, zap, and burp to gain a full picture of an application.

Answer: Web Application Tests

[Task 4] Scanning!#


Create a new 'Basic Network Scan' targeting the deployed VM. What option can we set under 'BASIC' to set a time for this scan to run? This can be very useful when network congestion is an issue.

Answer: Schedule


Under discovery set the scan to cover ports 1-65535. What is this type called?

Answer: Port scan (all ports)


As we are connected to the network via a VPN, it may be to our benefit to 'tone down' the scan a bit. What scan type can we change to under 'ADVANCED' for this lower bandwidth connection?

Answer: Scan low bandwidth links


After the scan completes, which 'Vulnerability' can we view the details of to see the open ports on this host?

Answer: Nessus SYN scanner


There seems to be a chat server running on this machine, what port is it on?

Answer: 6667

IRC Daemon Version Detection

The IRC server version is : ngIRCd-21. IPv6+IRCPLUS+SSL+SYSLOG+ZLIB-i686/pc/linux-gnu


Looks like we have a medium level vulnerability relating to SSH, what is this vulnerability named?

Answer: SSH Weak Algorithms Supported


What web server type and version is reported by Nessus?

Answer: Apache/2.4.99

The answer is in HTTP Server Type and Version which is grouped under HTTP (Multiple Issues): Apache/2.4.7. But the Apache HTTP Server Version grouped under Apache HTTP Server (Multiple Issues) reports Apache/2.4.99.

The room is expecting the wrong answer, obviously 2.4.99 is an invalid version that doesn't exist and is a false positive or a bug, 2.4.7 should be the correct answer.

[Task 6] So you're telling me that's how you set up a web app...#


What is the plugin id of the plugin that determines the HTTP server type and version?

Answer: 10107

HTTP Server Type and Version plugin.


What authentication page is discovered by the scanner that transmits credentials in cleartext?

Answer: login.php

The room is outdated so login.php won't show up in your scan.


What is the file extension of the config backup?

Answer: .bak

The room is outdated you can't find the answer by yourself.


Which directory contains example documents? (This will be in a php directory)

Answer: /external/phpids/0.6/docs/examples

The room is outdated, the server serving this page is down so you can't find it.


What vulnerability is this application susceptible to that is associated with X-Frame-Options?

Answer: clickjacking

The room is outdated, nessus can't find the vuln because the web server is not here anymore.


What version of php is the server using?

Answer: 5.5.9-1ubuntu4.26

The room is outdated, nessus find the version 5.5.9-1ubuntu4.14 but the room is expecting 5.5.9-1ubuntu4.26.