| name | performing-vulnerability-scanning-with-nessus |
| description | Performs authenticated and unauthenticated vulnerability scanning using Tenable Nessus to identify known vulnerabilities, misconfigurations, default credentials, and missing patches across network infrastructure, servers, and applications. The scanner correlates findings with CVE databases and CVSS scores to produce prioritized remediation guidance. Activates for requests involving vulnerability scanning, Nessus assessment, patch compliance checking, or automated vulnerability detection.
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| domain | cybersecurity |
| subdomain | penetration-testing |
| tags | ["vulnerability-scanning","Nessus","CVE","patch-management","Tenable"] |
| version | 1.0.0 |
| author | mahipal |
| license | Apache-2.0 |
Performing Vulnerability Scanning with Nessus
When to Use
- Conducting initial vulnerability assessment during the reconnaissance phase of a penetration test
- Performing periodic vulnerability scans to maintain compliance with PCI-DSS (requirement 11.2), HIPAA, or SOC 2 standards
- Validating that remediation efforts have successfully addressed previously identified vulnerabilities
- Establishing a baseline of known vulnerabilities before targeted manual exploitation
- Auditing patch compliance and configuration drift across server and workstation fleets
Do not use as a substitute for manual penetration testing, against systems without written authorization, or against fragile systems (medical devices, legacy SCADA) where scanning may cause service disruption.
Prerequisites
- Tenable Nessus Professional or Nessus Expert with current plugin updates (plugins should be less than 24 hours old)
- Network connectivity to all target hosts on all ports (no firewall restrictions between scanner and targets)
- Administrative credentials for authenticated scanning (domain admin or local admin for Windows, root/sudo for Linux, SNMP community strings for network devices)
- Target IP ranges and hostnames documented in the scope agreement
- Change management approval for scanning during authorized windows
Workflow
Step 1: Scan Configuration
Configure the Nessus scan policy based on engagement requirements:
- Scan type selection: Choose "Advanced Scan" for full control over plugin families, or "Credentialed Patch Audit" for patch compliance. Avoid "Basic Network Scan" for penetration tests as it uses a limited plugin set.
- Discovery settings: Configure port scanning to scan all 65,535 TCP ports and top 1,000 UDP ports. Set host discovery to use ARP (local), TCP SYN, and ICMP for maximum coverage.
- Authentication: Add Windows credentials (domain account with local admin), SSH credentials (key-based preferred over password), SNMP credentials (v3 with authPriv preferred), and database credentials for database-specific checks.
- Plugin configuration: Enable all plugin families relevant to the target environment. For penetration testing, ensure "Denial of Service" plugins are disabled unless explicitly authorized. Enable CGI scanning for web servers.
- Performance settings: Set maximum concurrent hosts per scanner (default 30, reduce for sensitive networks), maximum concurrent checks per host (4-5 for production, higher for test environments), and network timeout values appropriate for the target network.
Step 2: Scan Execution and Monitoring
