What is Network Pentesting?

Although today everyone talks about protecting apps, APIs, and mobile devices, network security doesn’t get the attention it deserves—and that’s a mistake. Failures in network infrastructure can open the door to devastating attacks, as was the case with the MOVEit incident in 2023.

That year, a vulnerability in the MOVEit file transfer software—widely used in sectors like healthcare, finance, and government—was massively exploited by the ransomware group CL0P. The result: more than 2,700 organizations compromised and the personal data of nearly 93 million people exposed. This breach proved that even seemingly secure systems can become attack vectors if not thoroughly audited.

The good news is that situations like this can be prevented. How? Through continuous network pentesting. Essentially, it involves allowing a security expert (an “ethical hacker”) to launch controlled attacks on your infrastructure to detect and fix vulnerabilities before someone with bad intentions finds them.

What Is Network Pentesting?

Network penetration testing, or network pentesting, is a specific type of pentest focused on evaluating a company’s entire network infrastructure in a controlled and ethical manner—just like a “good” hacker trying to find weaknesses before the bad ones do.

The main goal of these tests is to uncover vulnerabilities within the corporate network, from misconfigurations to unauthorized access points. To do this, different types of attacks are simulated, both from outside and inside the organization. This can range from external web application testing to more realistic scenarios like simulated phishing attacks, assessing the real resilience of both the network and staff against cyber threats.

Why Is It Important for Cybersecurity?

Because networks are the entry point to an organization’s entire digital infrastructure. A single firewall misconfiguration, a weak password, or an unnecessary open service can be enough to compromise an entire organization. Pentesting reveals those weak spots before it’s too late.

How Do Network Penetration Tests Work?

Network penetration tests are like a “cyberattack drill,” conducted by security experts known as ethical hackers or red teams. These professionals use tools and techniques similar to those used by real cybercriminals, with one goal in mind: to test the network inside and out to uncover vulnerabilities before malicious actors do.

In practice, this means simulating intrusion attempts to gain unauthorized access to the corporate network—bypassing firewalls, identifying weak points, and exploiting system vulnerabilities. These tests can target web applications, APIs, connected devices (endpoints), and even physical access controls, if within scope.

Additionally, these controlled attacks may directly target the operating system, allowing testers to uncover misconfigurations, outdated software, or poorly secured services. All of this provides valuable insight into the network’s most vulnerable points.

During these tests, experts may simulate real-world threats such as:

1. Distributed Denial of Service (DDoS) attacks

2. DNS exploitations

3. Targeted phishing campaigns

4. Malware distribution

5. SQL injection in web applications

These tests not only reveal where the risks are but also help measure the security team’s response, improve internal protocols, and reduce the actual attack surface.

Read more: Why Pentesting Is Key in a Cybersecurity Strategy

Types of Network Pentesting

In a network penetration test, specialists not only simulate attacks but also use automated tools and reconnaissance techniques to identify vulnerabilities more efficiently. Much of the process is divided into two main types of tests: internal and external.

Internal Network Tests

In an internal test, the security team simulates a scenario in which the attacker is already inside the network—like a malicious employee or someone who has obtained access credentials. The goal is to determine how far an internal attacker could go by exploiting excessive permissions or poorly managed configurations.

This type of simulation helps assess risks such as:

1. Theft of confidential data from within the network

2. Privilege escalation to access critical systems

3. Abuse of legitimate access to damage or leak information

It’s ideal for identifying weaknesses that perimeter security controls can’t detect.

External Network Tests

External tests, on the other hand, aim to simulate attacks from outside the organization—just like a cybercriminal with no prior access. The objective is to uncover vulnerabilities exposed to the internet, such as public servers, web applications, routers, or remotely connected employee devices.

Pen testers analyze everything visible from the outside that could serve as an entry point, including:

1. Corporate websites

2. Public APIs

3. Open and misconfigured ports

4. Poorly secured cloud services

This approach is essential for identifying security risks tied to an exposed attack surface and preventing unauthorized external access.

How Is a Network Penetration Test Conducted?

Conducting a network penetration test isn’t just about “checking how secure the network is.” It’s a methodical process that follows several well-defined stages with the goal of simulating real attacks, detecting vulnerabilities, and helping the organization strengthen its security.

At the end of the process, a detailed report is delivered summarizing the findings, business risks, and recommendations for improvement.

1. Planning and Information Gathering

Everything starts with solid planning. In this initial phase, ethical hackers (also known as pentesters) meet with stakeholders to define the test objectives, scope, and review any vulnerabilities the company has already identified. A preliminary vulnerability assessment is also conducted to get a clearer picture before starting the actual tests.

Next, success metrics, testing methods, and the types of tests to be performed are agreed upon based on the organization’s context. This is where the well-known testing approaches come into play: black box, gray box, and white box.

Types of Tests Based on Access Level:

2. Reconnaissance and Discovery

Once the approach is defined, it’s time to investigate. In this phase, the testing team gathers technical information about the target infrastructure: IP addresses, connected devices, exposed services, and more.

They may also use social engineering tactics to see if employees can be manipulated into granting access through deception (like phishing or simulated phone calls). All of this is done in a controlled and ethical manner.

Additionally, they use tools such as:

1. Port scanners (e.g., Nmap) to identify open and available services

2. Vulnerability scanners to detect known flaws in operating systems, applications, or configurations

This step is crucial to create a clear “map” of the potential attack paths a cybercriminal might exploit.

3. Penetration Test Execution

Now it’s time to act. Based on the information gathered, the pentesters begin simulating real attacks on the identified vulnerable points. This can include:

1. SQL injection in web applications

2. Unauthorized access attempts to servers

3. Execution of scripts to manipulate the system

4. Simulated data theft

5. Attempts to maintain persistence within the system without detection

The goal isn’t just to break in—it’s to see how far an attacker could go, how much damage they could cause, and how long they could remain undetected.

This phase also tests how the company’s security team responds: Do they detect the attack? Can they contain it? How quickly do they react?

4. Result Analysis and Final Report

Once the test is complete, the team documents all findings in a penetration test report. This report is one of the most important deliverables, as it includes:

1. What tests were conducted and how

2. Discovered vulnerabilities, with technical evidence

3. Risk level associated with each finding

4. Specific recommendations for remediation

5. Suggested priorities and next steps

This document is shared with the IT team, but it’s also translated into more accessible language for decision-makers. Why? Because it provides a clear, strategic view of the risks, helping the organization prioritize cybersecurity investments and make informed decisions.

Read more: Phases of Pentesting: How to secure your systems step by step?

Why Is Following This Process So Important?

It’s not just about seeing “if someone can hack me,” but about conducting a realistic and structured analysis of how an attacker could compromise your network—and what you can do to prevent it. Following this process helps to:

1. Identify weaknesses before real attackers do

2. Strengthen security policies and configurations

3. Educate staff about social engineering risks

4. Validate the effectiveness of firewalls, detection systems, and other controls

5. Comply with security standards and regulations like ISO 27001, PCI-DSS, or GDPR

Why Do Companies Perform Network Penetration Tests?

Network penetration tests are essential for protecting data and preventing attacks before they happen. Here’s why so many companies are implementing them:

1. Protect Critical Information: A pentest identifies real vulnerabilities in your network that could be exploited by cybercriminals, allowing you to close security gaps before they become a problem.

2. Evaluate Your Defenses: These tests show which security controls are working and which need improvement. It’s an effective way to verify the strength of your security infrastructure.

3. Prevent Data Breaches: By identifying and fixing weaknesses, you reduce the risk of data breaches—avoiding financial losses, reputational damage, and legal issues.

Network Pentesting FAQs

How often should I perform a network pentest?

Ideally once a year or after significant infrastructure changes.

Do I need advanced tools?

Not necessarily. What matters most is using the right tools effectively and adapting them to your specific context.

Is pentesting the same as vulnerability scanning?

No. Scanning identifies flaws; pentesting simulates real attacks to exploit them and measure their impact.

Can I do internal pentesting without a dedicated team?

Yes, but it’s best to have specialized personnel or hire external experts like TecnetOne.

Conclusion

Network security often takes a back seat to web and mobile app protection—but neglecting it can be a costly mistake.

Network pentesting is essential to detect vulnerabilities before attackers do. It’s not optional; it should be a core part of any serious cybersecurity strategy, along with continuous vulnerability scanning. The goal isn’t just to “see if something breaks,” but to prevent problems before they happen.

At TecnetOne, we can help you drastically reduce the risk of cyberattacks by integrating professional and recurring network penetration testing. Investing in this kind of protection not only keeps you safe—it also builds trust with your clients and stakeholders. And today, that trust is as valuable as the data you’re protecting.