Network Penetration Test in the PTaaS model: when it is needed and what it includes

The Network Penetration Test (NPT) is the module that validates infrastructure risk through targeted offensive simulations. Unlike a Vulnerability Assessment, which identifies known vulnerabilities, the NPT replicates real-world attack scenarios to verify how difficult it is to breach the perimeter and internal systems.

At ISGroup, the PTaaS (Penetration Testing as a Service) model is delivered through our Vulnerability Management Service (VMS), and the Network Penetration Test is part of the Advanced tier.

When to activate the Network Penetration Test

The NPT becomes necessary when a Vulnerability Assessment alone is not enough to answer critical questions about perimeter security:

• Infrastructures exposed to the Internet or internally segmented with critical assets
• Doubts regarding the actual robustness of the perimeter against a motivated attacker
• Need to validate both external and internal attack scenarios
• High-impact decisions that require concrete technical evidence

If your network supports critical services, sensitive data, or highly exposed external surfaces, the NPT included in the Advanced package is typically the most robust choice.

What the Network Penetration Test includes

The service covers three main areas:

• Technical simulation on network and services: replicates the techniques of a real attacker to identify compromise paths
• Validation of high-impact weaknesses: verifies whether the vulnerabilities detected by the VA are actually exploitable in realistic scenarios
• Operational output with corrective actions: detailed report with intervention priorities based on offensive evidence

The test can be conducted in black box (without prior information), grey box (with partial information), or white box (with full access to documentation) mode, depending on the objectives and the business context.

Why it is useful in the PTaaS journey

With only a Vulnerability Assessment, you may lack depth regarding real attack scenarios. The VA identifies known vulnerabilities, but it does not answer the question: “Would an attacker really be able to exploit them?”

The Network Penetration Test adds:

• Technical proof: demonstrates whether vulnerabilities are exploitable in practice
• Contextualization: evaluates the real impact by considering segmentation, access controls, and monitoring
• Remediation priority: helps focus resources on the critical issues that an attacker would exploit first

Relationship with other VMS modules

The Network Penetration Test integrates with the other services in the PTaaS journey:

• Vulnerability Assessment: provides the continuous baseline of known vulnerabilities
• Web Application Penetration Test (WAPT): adds application-level depth to web apps and APIs
• VMS: coordinates governance, priorities, and the closure of the remediation cycle

NPT and WAPT cover different surfaces and are complementary: the former focuses on infrastructure and perimeter, the latter on application logic and business logic.

Checklist for buyers and IT managers

Before deciding whether to activate the Network Penetration Test, consider these questions:

• Does the network support critical assets or sensitive data?
• Do you have highly exposed external surfaces (VPNs, portals, public services)?
• Do you want remediation priorities based on offensive evidence rather than just CVSS scores?
• Do you need to demonstrate the robustness of your perimeter to stakeholders or auditors?

If the answer is often “yes,” the NPT in the Advanced level of the VMS is the recommended choice.

Useful resources

If you want to better understand how the Network Penetration Test fits into the continuous security journey, these articles will help you navigate the different services and choose the level best suited to your needs:

• Complete guide to the ISGroup PTaaS model
• PTaaS and VMS: how they integrate
• Penetration Test in the PTaaS model
• Continuous Vulnerability Assessment in PTaaS
• Web Application Penetration Test in PTaaS
• VMS Standard vs Advanced: which one to choose

How to activate the service

To verify if your perimeter requires the Network Penetration Test in the Advanced package, book a free consultation from the ISGroup VMS page. The team will evaluate your business context and propose the most suitable path.

Frequently Asked Questions

• Should a Network Penetration Test be performed even if we have firewalls and segmentation?
• Yes, because the test verifies the actual effectiveness of the measures in attack scenarios, not just their formal presence. Firewalls and segmentation can be misconfigured or have exceptions that an attacker would exploit.
• Does the NPT replace the WAPT?
• No. NPT and WAPT cover different surfaces and are complementary in the PTaaS journey. The NPT focuses on infrastructure and perimeter, the WAPT on application logic and business logic of web apps.
• How long does a Network Penetration Test take?
• The duration depends on the complexity of the infrastructure and the objectives. A typical test requires 5 to 15 working days, including the reporting phase. ISGroup defines the scope and duration during the scoping phase.
• Can the NPT cause service disruptions?
• The test is designed to minimize operational impact. More invasive activities are agreed upon and scheduled during maintenance windows. ISGroup coordinates every phase with the IT team to avoid unplanned interruptions.
• What methodologies does ISGroup use for the NPT?
• ISGroup follows recognized methodologies such as OSSTMM and OWASP, integrated with up-to-date offensive techniques. The team combines automated tools and manual analysis to identify vulnerabilities that scanners do not detect.