How to select a network scanning tool

One of the most critical considerations when selecting a network scanning tool is its ability to discover every asset on your network. 

This goes beyond traditional on-prem devices to include virtual machines, cloud workloads, mobile devices, and, where applicable, operational technology (OT) like industrial control systems (ICS) or IoT devices.

Why does this matter? 

Attackers often exploit less visible or unmanaged assets to gain initial access. A scanner that only detects common devices may leave significant blind spots, putting your environment at risk. 

If your infrastructure spans multiple environments, choose a tool that will give you a unified visibility across your entire attack surface.

For example, some network scanners offer built-in support for cloud APIs to discover dynamic workloads and containers, while others specialize in scanning industrial environments. 

Understanding your asset landscape upfront helps you select a scanner with coverage tailored to your needs.

Want unified visibility across on-prem, cloud and OT environments? See how an integrated scanning solution can reduce cyber exposure.

Different scanning techniques serve different purposes. Look for a robust tool that supports active and passive scanning:

Active scanning sends probes to find open ports, services and vulnerabilities. It works great, but it can impact sensitive systems or set off intrusion detection alarms. 

Passive scanning quietly watches network traffic to spot devices and unusual activity without touching anything. This matters in places where active scans could cause problems, like hospital or manufacturing networks.

Agent-based scanning involves installing a lightweight software agent directly onto endpoints like laptops, servers and cloud instances. These agents report on vulnerabilities and configuration issues directly from the host for detailed and accurate data without network-wide probes or credentials. 

This method is ideal for covering a remote workforce, ephemeral cloud assets and devices frequently disconnected from your network.

Choosing a scanner that combines both methods gives you a complete and accurate picture of your network, so you can uncover transient devices or unauthorized connections that might otherwise slip through unnoticed. 

Passive scanning also provides continuous coverage, so you stay ahead of real-time changes.

While many scanners simply identify devices and open ports, the best tools go much further by identifying specific vulnerabilities. This includes missing patches, outdated or vulnerable software versions, misconfigurations and known exploit paths.

Look for scanners that integrate regularly updated vulnerability databases, like the National Vulnerability Database (NVD), the Common Vulnerabilities and Exposures (CVE) system, and other threat intelligence feeds so the scanner can always the latest threats and reduce false positives that can overwhelm your team.

For example, some advanced tools can correlate vulnerabilities with exploit availability so you have more context to prioritize remediation.

Credentialed or authenticated scanning significantly enhances vulnerability detection accuracy. This type of scanning enables the scanner to log in to systems and examine internal details like installed software, patch levels and security configurations.

This deeper visibility often uncovers issues that external scans miss, such as weak local permissions, missing security patches or unauthorized software. 

However, with credentialed scanning you’re responsible for managing and protecting those credentials. 

Choose tools that integrate with password vaults or credential managers to securely store and rotate access information without putting your sensitive data at risk.

Credentialed scans may also need coordination with other system owners and compliance policies, but its benefits and reduced false positives make it a worthwhile investment.

A powerful network scanning tool helps you move beyond raw data by offering accurate risk-based prioritization. 

For years, security teams relied almost exclusively on the Common Vulnerability Scoring System (CVSS), which often rates thousands of vulnerabilities as high or critical. 

Modern tools move beyond this static scoring by evaluating vulnerabilities based on a richer context, including active exploitability in the wild (i.e., is there known malware using this flaw?), severity, the business criticality of the affected asset, and its exposure to the internet. 

This multi-faceted approach helps your team focus remediation on the fraction of vulnerabilities that pose a genuine, immediate threat to your organization.

Look for scanners with customizable dashboards and reporting capabilities. 

Clear, concise reports facilitate communication with stakeholders — from technical teams to executives — making it easier to demonstrate security posture and justify investments.

Automated alerts for high-risk vulnerabilities or new asset discovery speed up response times to support continuous security.

Struggling with too many high-severity alerts? Learn how a vulnerability management tool with risk-based prioritization capabilities can help you focus on your most critical exposures.

Your network scanning tool should scale with you without increasing complexity. Ensure the tool can scale smoothly to cover expanding environments without causing performance bottlenecks. 

Look for features like distributed scanning engines you can deploy across different network segments or cloud environments, a cloud-native architecture that dynamically allocates resources and efficient data processing capabilities. These features ensure you can onboard new sites, cloud accounts or device types as your infrastructure evolves.

Consider whether the tool supports continuous scanning alongside scheduled scans, so you can tailor scanning intensity and frequency based on business needs and risk tolerance.

Scalable tools also make onboarding new sites, cloud accounts or device types easier as your infrastructure evolves.

Many organizations operate under strict regulatory frameworks such as PCI DSS, HIPAA, SOX or NIST. 

Selecting a network scanning tool with built-in compliance templates, automated reporting and audit-ready documentation simplifies meeting these requirements. 

These tools are fundamental to the check and act phases of the continuous improvement lifecycle (Plan-Do-Check-Act), central to many regulations.

Evaluate ease of use and integration

Finally, factor in how easy the tool is to deploy, configure and maintain. A user-friendly interface decreases configuration errors that could lead to missed vulnerabilities.

Integration with your existing security stack, such as vulnerability management platforms, ticketing systems, security information and event management (SIEM) systems and orchestration tools, so you can automate workflows and speed up incident response.

For example, integration with a SOAR platform can automate a complete workflow: 

1. Trigger: The network scanner detects a critical vulnerability, such as Log4j, on a public-facing web server.
2. Enrichment: The SOAR platform automatically queries the scanner for asset details, checks threat intelligence feeds for active exploits and looks up the system owner in a configuration management database (CMDB).
3. Action: It then creates a high-priority ticket in Jira or ServiceNow assigned directly to the server owner, simultaneously posting a notification to your security team.

Choosing the right network scanning tool requires balancing comprehensive coverage, detailed vulnerability detection, scalability, ease of use and regulatory support. 

By carefully evaluating these factors, and aligning them with your network and security goals, you can select a tool that strengthens your security posture, improves visibility and helps you respond swiftly to emerging threats.

Discover how Tenable Vulnerability Management can help you automate network scanning, prioritize risks and accelerate remediation.