Practical: Running a Basic Nessus Scan on a Real Machine

Running a basic Nessus scan on a real machine is straightforward and can help identify vulnerabilities and misconfigurations. Here’s a step-by-step guide to perform a basic scan using Nessus.

Prerequisites

1. Install and set up Nessus. Ensure it is installed on a system with access to the target machine.
2. Obtain the IP address or hostname of the target machine you wish to scan.
3. Verify that Nessus has proper permissions to scan the target (e.g., credentials for credentialed scans or authorization for network scans).
4. Ensure the target system has an active network connection.

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Step-by-Step Guide to Running a Basic Nessus Scan

Step 1: Log In to Nessus

• Open a web browser and navigate to the Nessus interface (e.g., https://<your-nessus-server-ip>:8834).
• Enter your credentials to access the Nessus dashboard.

Step 2: Create a New Scan

1. From the My Scans or All Scans folder, click the New Scan button.
2. Select a scan template. For a basic scan, choose Basic Network Scan. This template is designed to detect common vulnerabilities and open ports on the target.

Step 3: Configure the Scan

1. Name the Scan: Provide a name for your scan to identify it easily (e.g., “Basic Scan – TargetMachine”).
2. Add a Target: Enter the IP address, hostname, or range of the target machine(s).
3. Set Advanced Options (Optional): If needed, configure scan settings, such as port ranges or timeout values, under the Advanced Settings tab.
4. Save the Scan: Once all details are entered, click Save to store the configuration.

Step 4: Launch the Scan

• Locate the newly created scan in the My Scans folder.
• Click the Launch button to start the scan. Nessus will begin probing the target machine to identify vulnerabilities.

Step 5: Monitor the Scan

• The scan’s progress will be displayed in real time. You can click on the scan to view detailed progress and results as they are discovered.
• Scanning duration varies based on the number of targets, network speed, and system complexity.

Step 6: Review the Results

1. After the scan completes, click on the scan name to view the results.
2. Nessus will present a summary of findings, including:
   • Vulnerabilities: Categorized by severity (Critical, High, Medium, Low).
   • Open Ports: A list of detected open ports and associated services.
   • Plugin Details: Information about each identified vulnerability, including descriptions, remediation steps, and CVSS scores.

Step 7: Generate a Report

• To share or document the findings, generate a report by clicking the Export or Report option.
• Choose a format (e.g., PDF, HTML) and save the report for analysis or communication with stakeholders.

Step 8: Remediate Vulnerabilities

• Use the findings from the scan to prioritize remediation efforts.
• Address critical vulnerabilities first, such as applying patches, updating software, or closing unnecessary open ports.

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Practical Tips

• Start Small: For your first scan, target a single machine or a small network segment to get comfortable with Nessus.
• Use Credentialed Scans: Whenever possible, use system credentials to perform a deeper analysis, revealing vulnerabilities that non-credentialed scans might miss.
• Schedule Scans: Automate routine scans by configuring a schedule, ensuring continuous monitoring.
• Avoid Scanning Production Systems During Peak Hours: Scans can sometimes disrupt services, so run them during off-peak hours.

Running a basic Nessus scan provides valuable insights into the security posture of a machine or network. By following these steps, you can identify vulnerabilities, assess risk levels, and begin implementing remediation measures to improve your system’s security.