Nessus

Download Nessus

• https://www.tenable.com/downloads/nessus?loginAttempted=true

Register and Request Free Lincense

• https://www.tenable.com/products/nessus/activation-code

• Nessus Essentials.

Installing Pages (Linux)

• dpkg -i Nessus-8.15.1-ubuntu910_amd64.deb

Starting Nessus

• sudo systemctl start nessusd.service

Accessing Nessus

• https://localhost:8834

Scan Policies

• Are custom scans that can be preconfigured and saved / reapplied.

Plugin Rules

• Very good to exclude some ID’s that are just SSL-self certificates and basically false positives.

Scanning with Credentials

• Select Categorie and then accordingly, Username/PW or hashes or Whatever

Script to download scan Results in all different Formats

• https://raw.githubusercontent.com/eelsivart/nessus-report-downloader/master/nessus6-report-downloader.rb

• -./nessus_downloader.rb

Common Issues & Fixes

• all ports open / closed disable Ping the remote host in Advcanced Settings (stop scan from using ICMP)

• sensitive Networks: adjust Performance Options -> max concurrent Checks per host

• avooid scanning legacy systems (option to not scan pritners f.e.) in the rules.

• ALWAYS “safe checks” to not run DoS plugins. and inform that you are doing a check.

Checking for Impact of Nessus

• install vnstat:

• sudo apt install vnstat

• Check before running nessus scan:

• sudo vnstat -l -i eth0

• Check after running nessus scan:

• sudo vnstat -l -i eth0

• now we can compare number of bytes and packets transferred during a vuln scan.