Nessus

Nessus ↗ is an Automated Vulnerability Scanner. It was developed as an open-source project in 1998. It was later acquired by Tenable in 2005 and became proprietary software.

• It has extensive vulnerability scanning options and is widely used by large enterprises.
• It is available in both free and paid versions. The free version offers a limited number of scan features. In contrast, its commercial version offers advanced scanning features, unlimited scans, and professional support. Nessus needs to be deployed and managed on-premises.
• It has several features that allow you to perform continuous monitoring and compliance analysis.
• Nessus can be downloaded from https://www.tenable.com/downloads/nessus ↗.

NOTE Tenable also has a cloud-based solution called Tenable.io. For information about Tenable.io, see https://www.tenable.com/products/tenable-io ↗.

• Goto https://www.tenable.com/products/nessus/nessus-essentials ↗ and register an account.
• Download the package and to install download nessus file, dpkg -i [nessus file]
• To start: /etc/init.d/nessusd start
• Or you can start Nessus Scanner by typing /bin/systemctl start nessusd.service
• Then go to https://localhost:8834/ to configure your scanner
• Select Nessus Essentials, skip login and enter the activation key.
• Nessus will now install the plugins required for it to function.

Running Your First Scan#

• Create Scan: Click New Scan in the top right of the dashboard.
• Choose Template: Select a template like Host Discovery (to find live devices) or Basic Network Scan (for general vulnerability detection).
• Configure Targets: Name your scan, input the target IP address or subnet, and add optional authentication credentials for deep inspections.
• Launch: Click Save and Launch to run the assessment.

Analyzing Results#

• Review Findings: Open the completed scan from the My Scans folder. Vulnerabilities are color-coded by severity (Critical, High, Medium, Low, Info).
• Prioritize & Remediate: Focus on critical/high issues with known exploits, apply vendor patches or configuration updates, and rescan to verify fixes.