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Published: 20 December 2023

Contributors: Teaganne Finn, Amanda Downie

What is network penetration testing?

Network penetration testing is one type of penetration testing—or “pen test”—that specifically targets a company’s entire computer network through the practice of ethical hacking.

The goal of network penetration testing is to reveal and identify any vulnerabilities within the organization. This includes doing an in-depth evaluation of network security measures through external tests and internal tests, such as web application testing and mock phishing attacks.

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How does network penetration testing work?

The way network penetration works is that ethical hackers, or red teams, use hacking tools and techniques to do a mock cyberattack on an organization’s computer system. The aim is to get behind the organization’s firewall and gain unauthorized access.

Network penetration testing can include attacking web applications, APIs, endpoints, and physical controls. Simulated attacks on the operating system can reveal security weaknesses and show the organization where there are weak spots.

The fake attacks help security teams uncover pertinent security vulnerabilities to the network infrastructure. Common threats that can be tested include a distributed denial of service (DDos) attack, domain name system (DNS), malware, phishing, and SQL injection.

The testers also use tools to conduct recon and automate the pen testing process. There are often two types of tests used: internal and external.

Internal network tests: In an internal test, pen testers act as internal attackers or someone who may be trying to do a malicious act with stolen credentials. The main purpose of this type of test is to find vulnerabilities a person or employee might use from within the organization. This is done by stealing information and abusing privileges to access private or sensitive data.

External network tests: The external network penetration testing services are meant to mimic outside attackers trying to break into the network. These pen testers work to find security issues that are directly connected to the internet, such as servers, routers, websites, applications, and employee computers, which are open source risks.

The network penetration testing process

Often a network penetration test follows four specific steps. The test concludes with a network pen test report, which is a detailed analysis of business risks and the risk findings.

1. Gather information and plan

In this first phase, the ethical hackers discuss with key stakeholders what the overall goal of the testing will be and what vulnerabilities the organization has identified. Before pen testing a vulnerability assessment should be done.

From there, the pen testers and stakeholders decide which tests to perform and the success metrics they plan to use. Testers use several different tools and methodologies to perform the fake attacks, such as port scanning and network mapping (nmap).  

There are three types of test perspective commonly used. Depending on the organization, these can be used individually or combined.  

Black box testing: A ‘black box’ test is conducted from the perspective of an average hacker with little or no internal knowledge about the network system. This type of testing would be an external pen test since its goal is to exploit outward-facing vulnerabilities within the network.

Gray box testing: This type of network penetration test has more of an internal focus and aims to portray a hacker with access to the internal system. While also maintaining some of the aspects of an external hacker. The gray box test aims to be a bad actor within an organization who may have elevated privileges that are being used in a malicious way.

White box testing: Finally, the white box test is the most intrusive of the three security testing types. This test is performed to portray an IT specialist or someone with access to the organization’s source code and all possible data about the system. This test is typically performed last to test the integrity of an IT architecture. And further ensure possible hackers and cyberattacks to the target system are impenetrable. 

2. Conduct reconnaissance and discover

In the reconnaissance and discovery phase, pen testers take data from the reconnaissance to perform live tests and discover the existing vulnerabilities through tactics, such as social engineering. By using deceptive tools to manipulate individuals into sharing information, the pen testers hope to find where the weak spots are located and target those vulnerabilities.

In the discovery step, pen testers may use tools like a port scanner and vulnerability scanner. The port scanner identifies open ports on a system where hackers might get in and a vulnerability scanner identifies existing vulnerabilities on a system.

3. Perform the network penetration test

This next step is to put all the preliminary work that is done up to this point into action. In this step, the pen testers perform the network penetration tests by using tools that can exploit scripts or attempt to steal data. The purpose is to figure out how much damage the ethical hackers can cause and if they do gain access, determine how long they can stay within the system.

Pen testers can start by testing one vulnerability at a time but should perform tests on multiple vulnerabilities to ensure that a broad approach is taken to address these security risks.

4. Analyze and report information

The final step is to document what network penetration tests were performed then go over the results of each of those tests and discuss remediation steps with the information security team. The report details the entire process from start to finish and identifies the vulnerabilities, evidence, data, and recommendations for the organization. This report is important for the business owner to have a full picture of what risks have been identified and an analysis that further helps them make informed decisions. 

Why companies network penetration test
Protect your data

An organization faces many threats and having guardrails on your data is vital to protecting your business and its sensitive information. A network penetration test identifies all vulnerabilities and protects your organization’s data from all possible entry points. While a vulnerability scan can be beneficial, it is not as extensive of a testing tool and, if anything, should be used as a supplement to a pen test.

Understand your security controls

By performing pen testing, you have a better understanding of what security controls are working and which need to be strengthened. The network penetration testing also gives the organization the ability to analyze its security posture.

Prevent data breaches

Preemptively analyzing your organization’s network vulnerabilities ensures that the chances of a data breach are almost eliminated. Pen testing improves overall security through security assessments and cybersecurity scans.

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