Customer Instructions - Computer Security Add-On Installation: Tenable Nessus

Table of Contents

Overview

As part of your vCISO service, we scan your computer for vulnerabilities that could be used by hackers.

The scanner is made by Tenable (https://www.tenable.com/).  The scanner has two parts:

  1. a small program on your computer
  2. a cloud console to view vulnerabilities

 

This scanner has no access to files or sensitive data as part of the scans.  It is only checking your computer settings against a database of tens of thousands of ways that hackers can get in.

Disclaimer

Adelia Risk tests and uses all of the products described below before providing them to Client.  However, there is always a possibility that security products will conflict with parts of Client’s IT infrastructure.  In case of a conflict, Adelia Risk will make best efforts to resolve the conflict.  If a conflict can’t be resolved, the product will be removed from this agreement and the monthly subscription fee will be adjusted appropriately.

Simple Two Step Install

Here’s all you need to do:

  1. Follow the instructions below to install the scanner on all computers and servers.
  2. Add allow-listing rules in your anti-virus program (e.g. Sentinel One, Crowdstrike) as per https://docs.tenable.com/agent/Content/Allowlist.htm 

Need help?

Need help with these instructions?  Shoot us an email at support@adeliarisk.com.

Windows Installation for IT Pros

To deploy to multiple computers, most IT pros will push a copy of the appropriate Nessus agent to a temp folder on each computer, and then will use a command-line script to install and clean up post install.

For example, a sample command that might work for you is:

msiexec /i C:\Temp\NessusAgent.msi NESSUS_GROUPS=”request_from_support@adeliarisk” NESSUS_SERVER=”cloud.tenable.com:443″ NESSUS_KEY=request_from_support@adeliarisk /qn

IMPORTANT: Please note that you need the double-quotes before and after the NESSUS_GROUPS value.

If this starter script doesn’t work for you, use the documentation from Nessus to build your own command-line instructions: https://docs.tenable.com/nessus/Content/InstallNessusAgentWindows.htm

Please email us at support@adeliarisk.com and let us know that your Tenable Nessus is installed so we can confirm we see it on our side.  If possible, please tell us your computer names where you pushed the agent.

Windows Deployment & Patching Options

Here are some techniques our other clients have used: 

  • If you’re just pushing to a few machines, have users manually install (per instructions below).  This isn’t the recommended approach for any but the smallest of companies, because someone will need to remember to install it again on new or re-imaged computers.
  • Use Microsoft InTune, and write a PowerShell script that first checks for the presence of the agent and if it doesn’t find it, that follows the instructions above to deploy it.
  • Use a Remote Monitoring and Management (RMM) tool to push the software out, and to make sure that it’s always installed.  IT managed service providers typically use tools like ConnectWise and Ninja.  Internal IT teams often use tools like SolarWinds and ManageEngine.
  • One inexpensive and highly effective tool that we’ve seen some teams use is NinitePro.  It’s great for pushing out software and installing patches.  In fact, some IT MSP’s use NinitePro in addition to their RMM because it does a much better job of managing patches.  With that said, NinitePro is missing a lot of the other features typically found in an RMM tool, so you should do your due diligence.

Windows Installation for Users

Here are instructions for installing Tenable on your Windows computer. It should take you less than 5 minutes.

First, download the correct agent from the Tenable Agents page: https://www.tenable.com/downloads/nessus-agents

install_windows_tenable_agent_adeliarisk

Don’t worry if the version number is higher than the 11.0.3 pictured. Just pick the most recent one.

Next, follow the wizard until you reach a screen that looks like this:

Tenable security configuration wizard setup screen

Here’s what to enter:

  • Key: email support@adeliarisk.com to request
  • Server: cloud.tenable.com:443
  • Groups: email support@adeliarisk.com to request request_from_support@adeliarisk

 

IMPORTANT: all of these are case sensitive.  Please copy and paste them directly.  

Mac Installation for Users

Here are instructions for installing Tenable on your Windows computer. It should take you less than 5 minutes.

First, download the correct agent from the Tenable Agents page: https://www.tenable.com/downloads/nessus-agents

install_mac_tenable_agent_adeliarisk

Don’t worry if the version number is higher than 11.03 pictured. Just pick the most recent one.

Open the .dmg file, and then click on “Install Nessus Agent.pkg” to install the software.

Tenable security scan running on Mac computer

Follow the installation wizard until it’s complete.

Connect the Agent to the Cloud

Now, we need to tell the Nessus agent how to talk to us. 

On your Mac, go to Applications > Utilities and open the “Terminal” program.

Copy and paste the following in to your Terminal window, then press the return key:

cd /Library/NessusAgent/run/sbin/

Now copy and paste the following in to your Terminal window, then press the return key:

sudo ./nessuscli agent link –key=request_from_support@adeliarisk –host=cloud.tenable.com
–port=443 –groups=”
request_from_support@adeliarisk


IMPORTANT:
 all of these are case sensitive.  Please copy and paste them directly. 

ALSO: Please note that you need the double-quotes before and after the groups value.

You’ll probably need to enter your computer’s password after issuing this command. Don’t worry — we don’t get a copy of your password.

Incorrect Machine Names

If you find that the computer name in tenable[.]io doesn’t match the computer name on your Mac, this is due to a bit of a confusing setup for how Macs manage machine names.  

Macs have three different machine names:

  • HostName (scutil –get HostName) – this is not editable in the macOS GUI
  • LocalHostName (scutil –get LocalHostName) – the “Bonjour” name (e.g., MacBook-Pro.local) set at System Settings > General > Sharing > Local Hostname.
  • ComputerName (scutil –get ComputerName) – the friendly name from System Settings > General > About.

 

Here’s why you’re seeing inconsistencies in these names — Tenable uses #1 (HostName) for their names.

However, HostName is often left blank (because it’s not editable in the GUI). If it’s blank, then the computer uses LocalHostName as the name (and Tenable will pick that up instead).

Here’s how to fix it.  Run this command in Terminal on the Mac:

sudo scutil –set HostName <Desired-Name>

That will change the HostName, and you can make it the same as LocalHostName and ComputerName from the GUI.

Uninstalling the Tenable Agent

Need to un-install Tenable?  Here are the instructions: https://docs.tenable.com/agent/Content/RemoveNessusAgent.htm