Network scanning vs vulnerability scanning

Network scanning is a process that typically involves two key phases: network discovery and port/service scanning. This process discovers and maps every device connected to your network and the services they are running.

Imagine you’re hosting a large event and need to take attendance. You want to know who is present, their location and what they have with them. 

Network scanning does precisely that for your IT environment.

A network scanner probes your network to find:

Active devices (network discovery): Identifies active IP addresses corresponding to servers, laptops, mobile phones, printers, cloud workloads and more.

Open ports and services (port scanning): For each discovered device, it identifies which network ports are open and which services run on them. For example, a server might have port 22 open for Secure Shell (SSH) or port 80 for web traffic (HTTP).

Network scans help you build a detailed inventory of everything on your network, including unknown or unmanaged devices.

Vulnerability scanning analyzes your assets for exposures hackers could exploit, like:

• Missing security patches or updates
• Old or buggy software versions
• Weak passwords or default logins
• Bad settings that expose systems
• Known security issues

For example, a vulnerability scan might find that the SSH service on a server is running a version with a critical remote code execution flaw, or that a user account lacks multi-factor authentication, which increases compromise risk.

Network scanning and vulnerability scanning are closely intertwined and work best when used in tandem. 

Think of the process as a logical sequence. Network discovery and port scanning are the first steps, so you have a continuously updated, comprehensive map of all devices and running services.

This asset and service inventory is a direct input for vulnerability scanning. The vulnerability scanner then systematically assesses the security posture of each identified asset and service. 

Without network scanning, vulnerability scanning can only target known assets. 

If new devices or shadow IT components, like unauthorized laptops, IoT devices or cloud workloads, can pop up unnoticed, so vulnerability scans might not find them. This leaves security gap attackers can exploit. 

Regular network scanning ensures you keep track of every asset, no matter how dynamic or complex your environment is.

Once network scanning identifies all devices and open services, vulnerability scanning uses this inventory as its starting point. It performs detailed checks on each device, looking for weaknesses such as missing patches, outdated software or misconfigurations. 

When you add vulnerability scanning to network scanning, you get a ranked list of security problems based on what's in your environment, not guesswork or incomplete info.

Network scanning can also spot changes as they happen, like new devices popping up or altered service settings, and kick off targeted vulnerability scans right away.

This back-and-forth cycle keeps you aware of security issues and shrinks the window hackers have to strike.

In practice, combining both lets you:

• Keep accurate, up-to-date visibility of your assets
• Find vulnerabilities across all discovered devices and services
• Focus fixes based on risk and asset criticality
• Find unauthorized or rogue devices
• Meet compliance requirements with network visibility and vulnerability management

When you combine network scanning and vulnerability scanning, you get a layered defense that discovers what's on your network and where you're exposed.

Both network and vulnerability scanning can use different approaches:

Unauthenticated scans act like an outside hacker would. They probe your network without any credentials to find vulnerabilities on your perimeter. These scans help you understand what outsiders can see about your network, but they tend to create more false alarms.

Authenticated scans log in to systems using provided credentials to perform checks from the inside. This credentialed approach is a more accurate, low-level view of an asset's security posture, where you can find missing patches, insecure local configurations and other invisible issues from the outside.

Combining both scan types gives you a more holistic security picture, exposing risks from outside and inside perspectives.

If you only do network scanning, you'll know what devices and services are out there, but you won't know how easy they are to breach.

On the flip side, running vulnerability scans without knowing what's actually on your network means you'll miss exposures, which could leave you wide open to attacks.

When you use network scanning and vulnerability scanning together, you get:

Complete network visibility so you never lose track of devices or services 

Accurate vulnerability assessment to find and prioritize your risks

Stronger risk management by fixing your cyber risk first

Looking for a smarter way to combine network and vulnerability scanning? See how Tenable Vulnerability Management simplifies visibility and reduces risk.

Think of network scanning and vulnerability scanning as two parts of one ongoing, connected process that’s the core of your security program.

The following nine best practices align with leading cybersecurity frameworks, like Center for Internet Security (CIS) Controls, to help you get the most from both:

1. Keep an accurate, current asset inventory

• Set up regular network scans to catch all devices in your environment, like on-prem, cloud workloads, mobile devices and IoT.
• Scanning can spot new or unauthorized devices fast and decrease exposures.
• Use automated tools that update your inventory in real-time as your network changes.

2. Base vulnerability scans on your network inventory

• Use your current asset list as the starting point for vulnerability scans.
• Don't skip any devices, services or network areas in your assessments so you can find all your exposures across everything attackers might target, not just part of it.

3. Mix unauthenticated and authenticated scanning

• Unauthenticated (external) and authenticated (internal) vulnerability scans give you important info.
• Unauthenticated scans show you what an attacker sees, finding vulnerabilities they could spot without login credentials.
• Authenticated scans go deeper, getting inside system details to find hidden problems like missing patches or bad configurations.
• Using both gives you the full security picture.

4. Prioritize vulnerabilities with risk-based scoring

• Use risk-based prioritization models that consider factors like exploit availability, asset criticality and potential business impact so you can focus remediation on exposures that create actual risk for your unique environment.

5. Automate scanning and alerts where possible

• Automate scan scheduling and vulnerability detection for continuous coverage without manual intervention.
• Set up real-time alerts for critical vulnerabilities, new device discovery or significant network changes so your team can proactively and quickly respond.

6. Customize scan policies for different network segments

• Tailor scanning intensity, frequency and scope based on asset types and risk levels.
• Critical servers and sensitive systems may require more frequent, deeper scans, while less critical devices can be scanned less aggressively.
• Customization reduces false positives and minimizes impact on network performance.

7. Integrate scanning with your broader security workflows

• Ensure scan results feed into your vulnerability management, patch management and incident response platforms.
• Integration streamlines workflows by automating ticket creation, remediation tracking and compliance reporting.

8. Train your security and IT teams

• Scanning tools generate large volumes of data that can overwhelm if not properly interpreted.
• Provide training so your teams understand scan reports, how to assess risk and how to prioritize remediation.
• Encourage collaboration between network, security and operations teams to speed resolution.

9. Regularly review and update scanning strategies

• As your network changes and new threats emerge, revisit your scanning policies and tools.
• Update schedules, scope and scanning methods to align with current business needs and threat landscapes.
• Continuous improvement ensures your scanning program is always effective and relevant.

Following these best practices, you can build a scanning program with comprehensive visibility, accurate vulnerability detection and streamlined remediation. This layered approach reduces risk and helps defend your network against increasingly sophisticated threats.

Ready to strengthen your defenses with unified network and vulnerability scanning? Discover how Tenable Vulnerability Management can help you gain complete visibility, prioritize risks and accelerate remediation.