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Nessus

Vulnerability Analysis

Intermediatehigh risk

Nessus is a proprietary, industry-standard vulnerability scanner designed to provide comprehensive point-in-time assessments tracking active service flaws, malware presences, and network infrastructure misconfigurations.

Installation

systemctl status nessusd || dpkg -i Nessus-<version>.deb && systemctl start nessusd

Basic Syntax

Access via https://localhost:8834

Quick Facts

Full Name
Nessus Vulnerability Scanner
License
Proprietary (Free Essentials)
Plugins
100,000+
Interface
Web GUI
Category
Vulnerability Scanner
Vendor
Tenable

Tool Overview

Nessus is a proprietary vulnerability scanner designed for comprehensive point-in-time assessments of active service flaws, malware presence, and network infrastructure misconfigurations.

The tool provides a web-based interface for scan configuration, execution, and reporting. It supports credentialed scanning for deep assessment and compliance checking for various standards.

Nessus is the industry standard for vulnerability scanning, used by enterprises worldwide for security assessments, compliance auditing, and vulnerability management programs.

Common Commands

systemctl start nessusdStart Nessus service - Begin scanning session
systemctl stop nessusdStop Nessus service - End scanning session
/opt/nessus/sbin/nessuscli updateUpdate plugins - Before scanning for latest vulns
/opt/nessus/sbin/nessuscli fix --reset-allReset Nessus configuration - Troubleshooting issues
Basic Network ScanScan for common vulnerabilities
Advanced ScanDeep vulnerability scan with custom policies
Credentialed ScanScan with login credentials for deeper analysis
systemctl status nessusdCheck service status
systemctl restart nessusdRestart Nessus daemon
/opt/nessus/sbin/nessuscli update --allForce full update
/opt/nessus/sbin/nessuscli user listList users
/opt/nessus/sbin/nessuscli user add adminAdd user
/opt/nessus/sbin/nessuscli user passwd adminChange password
/opt/nessus/sbin/nessuscli user delete adminDelete user
/opt/nessus/sbin/nessuscli fetch --register CODERegister activation code

Step-by-Step Guide

  1. 1Obtain the appropriate installation package from the vendor's website
  2. 2Install the package using your system's package manager
  3. 3Start the background service daemon
  4. 4Navigate to the web portal at https://localhost:8834
  5. 5Create an admin profile and input your activation code
  6. 6Wait for the vulnerability plugins to finish downloading and compiling
  7. 7Set up a new scan project pointing to your authorized targets
  8. 8Select an appropriate policy profile for your objective
  9. 9Launch the scan and watch the progress bar
  10. 10Analyze the completed dashboard and export a detailed PDF or HTML report

Warnings

Use Cases

Vulnerability Scanning

Comprehensive network vulnerability assessment.

Compliance Auditing

Verify systems meet compliance standards.

Credentialed Scanning

Deep assessment with login credentials.

Report Generation

Professional vulnerability reports for stakeholders.

Key Features

Related Tools

OpenVAS

Vulnerability Analysis

Open source vulnerability scanner.

Lynis

Vulnerability Analysis

Host-based security auditing.

Frequently Asked Questions

What is Nessus used for?

Nessus is a vulnerability scanner that checks systems for misconfigurations, default passwords, and known vulnerabilities. It provides comprehensive network vulnerability assessments with detailed reporting.

Is Nessus free?

Nessus offers a free 'Essentials' version limited to 16 IP addresses. The Professional version is commercial with unlimited IPs and advanced features.

How does credentialed scanning work?

Credentialed scanning uses login credentials to perform deeper checks, including installed software, registry keys, and local vulnerabilities that unauthenticated scans cannot detect.

Can Nessus check compliance?

Yes, Nessus includes compliance checks for PCI DSS, HIPAA, CIS benchmarks, and other standards. It verifies system configurations against compliance requirements.

How do I install Nessus?

Download the installer from tenable.com, install using your package manager, then start the service: systemctl start nessusd. Access the web interface at https://localhost:8834.

How do I start Nessus?

Run systemctl start nessusd to start the Nessus service. Access the web interface at https://localhost:8834 and complete the initial setup.

What are the most common Nessus commands?

Common commands include: systemctl start nessusd (start), systemctl stop nessusd (stop), /opt/nessus/sbin/nessuscli update (update plugins).

How do I update Nessus plugins?

Run /opt/nessus/sbin/nessuscli update to download the latest vulnerability plugins. Update regularly to catch new vulnerabilities.

How does Nessus compare to OpenVAS?

Nessus is commercial with 100,000+ plugins and faster updates. OpenVAS is free and open source with 50,000+ tests. Nessus has better support; OpenVAS is budget-friendly.

Is Nessus legal to use?

Nessus itself is legal software. However, scanning networks without permission from the owner may violate laws. Always obtain written authorization before scanning.

What is Nessus Essentials?

Nessus Essentials is the free version of Nessus, limited to 16 IP addresses. It provides basic vulnerability scanning for small environments or learning purposes.

How do I configure a Nessus scan?

Access the web interface, create a new scan, select a scan template, configure targets and credentials, then launch the scan. Results appear in the reports section.

What scan types does Nessus offer?

Nessus offers Basic Network Scan, Advanced Scan, Credentialed Patch Audit, Web Application Scan, and compliance-specific scans. Choose based on your assessment needs.

How long does a Nessus scan take?

A basic network scan takes 30-60 minutes. Credentialed scans and full scans can take 1-4 hours depending on the target range and configuration.

What is the Nessus plugin database?

The plugin database contains 100,000+ vulnerability checks. Plugins are regularly updated to cover new CVEs and vulnerabilities.

How do I export Nessus results?

Export reports as PDF, HTML, CSV, or Nessus format from the web interface. Reports include vulnerability details, CVSS scores, and remediation guidance.

What is Nessus credentialed scanning?

Credentialed scanning uses login credentials to perform deeper checks, discovering local vulnerabilities, installed software, and misconfigurations that unauthenticated scans miss.

How do I access Nessus web interface?

Start Nessus with systemctl start nessusd and access https://localhost:8834 in your browser. Complete the initial setup wizard on first login.

Tags

#vulnerability-analysis#network-scanner#compliance#enterprise-audit

Output Explanation

The interface displays vulnerabilities grouped by severity risk: Critical (Red), High (Orange), Medium (Yellow), Low (Green), and Informational (Blue). The output includes detailed descriptions, CVE references, CVSS scores, and instructions for applying patches.

Ethical Usage Notice

This tool is designed for authorized security testing, educational purposes, and legitimate network administration only. Unauthorized access to computer systems is illegal.