How To Conduct Vulnerability Scanning with Nessus

Vulnerability scanning with Nessus is a critical step in securing your network and identifying weaknesses that attackers could exploit. Nessus, developed by Tenable, is a powerful vulnerability scanner that detects misconfigurations, outdated software, and security flaws in devices, servers, and applications. This guide explains how to set up and use Nessus effectively for vulnerability scanning.

What Is Nessus?

Nessus is a vulnerability scanning tool designed to help organizations identify and remediate security risks. It supports scanning for vulnerabilities across various systems, including operating systems, applications, databases, and network devices.

Key Features of Nessus:

• Comprehensive Coverage: Detects a wide range of vulnerabilities, including CVEs and misconfigurations.
• Ease of Use: Provides a user-friendly interface for setting up and running scans.
• Customizable Scans: Allows fine-tuning of scan policies and configurations.
• Actionable Reports: Generates detailed reports with recommended remediation steps.

Steps to Conduct Vulnerability Scanning with Nessus

1. Install and Set Up Nessus

Download Nessus

1. Visit the Tenable website.
2. Choose the appropriate Nessus version:
   • Nessus Essentials: Free for personal use.
   • Nessus Professional: Designed for professional vulnerability assessments.
3. Download the installer for your operating system (Windows, Linux, or macOS).

Install Nessus

1. Run the downloaded installer.
2. Follow the on-screen instructions to complete the installation.
3. Access the Nessus web interface at https://<IP>:8834.

Activate Nessus

1. Enter your activation code (provided during registration).
2. Allow Nessus to update its plugins, which contain vulnerability definitions and scanning capabilities.

2. Configure a Vulnerability Scan

Add a New Scan

1. Login to Nessus: Use your credentials to access the Nessus interface.
2. Create a New Scan: Click on New Scan in the Scans tab.
3. Select a Scan Template: Choose from options like:
   • Basic Network Scan: For general vulnerability assessments.
   • Advanced Scan: For custom configurations and specific targets.
   • Web Application Tests: For web server vulnerabilities.

Configure Scan Settings

1. Name and Description: Provide a name and optional description for the scan.
2. Target Selection: Enter the IP addresses, ranges, or hostnames of the systems you want to scan.
3. Authentication (Optional): Configure credentials (e.g., SSH, Windows credentials) for authenticated scans, which provide deeper insights into vulnerabilities.
4. Policies: Adjust scan settings like port ranges, plugins, or detection methods.

3. Run the Scan

1. Navigate to the Scans tab and locate your configured scan.
2. Click Launch to start the scan.
3. Monitor progress in real-time as Nessus scans your targets.

4. Analyze Scan Results

Once the scan is complete, review the findings to understand your network’s vulnerabilities.

• Summary Dashboard: View an overview of vulnerabilities sorted by severity (Critical, High, Medium, Low).
• Detailed Vulnerabilities: Drill down into individual findings for specific details, including affected systems, vulnerability descriptions, and CVE references.
• Export Reports: Export reports in formats like HTML, PDF, or CSV for documentation or sharing with stakeholders.

5. Remediate Identified Vulnerabilities

Prioritize remediation efforts based on severity and potential impact.

• Critical and High Risks: Address these vulnerabilities immediately, as they pose the greatest threat.
• Apply Patches: Update software, operating systems, and applications to the latest versions.
• Reconfigure Settings: Fix misconfigurations, such as weak passwords or open ports.
• Validate Fixes: Rerun scans after remediation to confirm vulnerabilities have been resolved.

6. Schedule Regular Scans

To maintain a secure environment, schedule regular scans to identify new vulnerabilities.

• Frequency: Conduct scans weekly, monthly, or after major system changes.
• Automation: Use Nessus’s scheduling feature to automate scans during off-peak hours.
• Policy Updates: Regularly update scan policies and plugins to keep up with emerging threats.

Best Practices for Nessus Vulnerability Scanning

• Segment Scans: Break scans into smaller segments to reduce network impact.
• Use Authentication: Authenticate scans to detect deeper vulnerabilities.
• Restrict Access: Limit who can view and launch scans to prevent misuse.
• Integrate with SIEM Tools: Enhance monitoring by integrating Nessus with security tools like Splunk or QRadar.

Frequently Asked Questions About Conducting Vulnerability Scanning with Nessus