What Is Penetration Testing? (Plus Stages and Types)

By Indeed Editorial Team

Published September 27, 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

An ethical hacker is an information technology (IT) expert who uses hacking methods to identify potential points of entry into a company's network. Penetration tests, also known as pen tests or ethical hacking, involve a type of cybersecurity technique organizations use to identify, test, and highlight security vulnerabilities. Understanding how penetration tests work can help you enhance the security of an organization's network systems. In this article, we answer the question, "What is penetration testing?", discuss why pen testing is important, outline its difference from vulnerability testing, review its stages, and list various methods.

What is penetration testing?

You may be wondering, "What is penetration testing?" if you're interested in improving a system's security. Pen testing comprises scaling planned attacks against a company's security infrastructure to identify potential vulnerabilities. Penetration testing is an integral component of a comprehensive web application security program. The purpose of pen testing is to breach various application systems, including application protocol interfaces (APIs), and frontend and backend servers.

Performing breaches can uncover vulnerabilities, such as inputs that are susceptible to coding hacks. The goal of penetration testing is to simulate different attack vectors, either externally or internally. Depending on the test, penetration testers may or may not be familiar with the environment and system they're attempting to compromise.

Related: How to Become a Penetration Tester (Step-by-Step Guide)

Why is pen testing important?

Penetration testing is an important component of cyber security strategy, as it provides an opportunity for an organization to validate the security of its systems, applications, and networks. This procedure is beneficial to an organization because it enables them to identify and remedy weaknesses before hackers can exploit the vulnerabilities. A penetration test also provides a way to test the effectiveness of a system's defence mechanisms. A better design of security processes and security controls usually helps the organization improve the effectiveness of its security operations.

Related: How to Get Started in a Professional Ethical Hacking Career

Differences between penetration testing and vulnerability testing

A vulnerability test provides valuable insight into the security of a network on a weekly, monthly, or quarterly basis. Penetration tests provide a more comprehensive analysis of a network's security. A vulnerability test is an automated, high-level test designed to identify potential vulnerabilities on a network. Penetration testing involves a detailed, hands-on examination of a system by a trained professional who seeks to detect and exploit weaknesses. Also known as vulnerability scans, vulnerability tests assess computers, systems, and networks for security weaknesses.

A high-quality vulnerability scan can detect over 50,000 vulnerabilities. Vulnerability tests are passive approaches to vulnerability management because they only identify and report vulnerabilities. IT professionals patch weaknesses as necessary or verify that false positives aren't present before running the test again. The vulnerability scanner generates a report following the completion of the test. A vulnerability test typically generates a comprehensive list of vulnerabilities and references for further investigation. The results of some tests may also include instructions on how to resolve the problem.

Related: 10 Top Security Certifications for IT Professionals

Stages of penetration testing

Learning more about penetration testing can lead you to inquire more about its various stages, including the following:


In the planning stage, ethical hackers simulate a malicious attack that allows them to gather as much information as possible about the target system. During this stage, ethical hackers examine the system, note any vulnerabilities, and learn how the organization's technology stack reacts to system compromises. Pen testers search through a wide variety of information, including names, e-mail addresses, and employee IP addresses. Depending on the objectives of the analysis, the type of information or the depth of the investigation may vary. Methods of gathering information include social engineering, network scanning, and retrieval of domain registration information.


During the scanning phase, penetration testers examine the weaknesses of the system and network based on the findings of the planning phase. This phase of the pen test identifies the weaknesses of the system that hackers may exploit for targeted attacks. The accuracy of all this information is critical, as it can determine the success of the subsequent phases of the pen test.

Related: What Is a Network Firewall? (With Key Terms and Benefits)


By exploiting the system's vulnerabilities, pen testers infiltrate the infrastructure. As a next step, they attempt to further exploit the system by escalating privileges to demonstrate the depth to which they can penetrate the target environment. To discover a target's vulnerabilities, this stage involves web application attacks, such as cross-site scripting, SQL injection, and backdoors. The next step is to exploit the vulnerabilities by increasing privileges, intercepting traffic, and stealing data to gain a better understanding of the potential damage.


The purpose of the exploitation stage is to identify the potential consequences of exploiting a vulnerability. Once penetration testers gain access to a system, they maintain access and simulate an attack to mimic the malicious intentions of the hackers. Ethical hackers attempt to secure the maximum level of privileges, network information, and access to as many systems as possible by identifying the data or services that are available. A user account's access privileges refer to the specific rights and abilities granted to that account.

Related: What Is Web Testing? (With Definition, Types, and Examples)


The reporting phase demonstrates the potential consequences of a security breach for businesses, customers, and clients. Following the completion of the penetration testing, the testing team creates thorough reports. A well-written penetration test report summarizes the results and findings of the assessment. It contains information regarding all findings, a list of targets, exploits used, and solutions to the issues encountered.

Related: What Is System Integration Testing and How to Perform It?

Penetration testing methods

The following are various methods for penetration testing:

External penetration testing

External penetration testing involves the testing of non-production targets, external to the organization's network and infrastructures, such as service providers and business partners. An external penetration test aims to identify and exploit vulnerabilities and gain access to an organization's internal network. An external penetration test can also provide valuable insight into the weak points in an organization's defences that may allow an attacker to gain access to the internal network.

Internal penetration testing

Internal penetration testing is one of the most effective ways of protecting an organization against insider threats. Internal penetration allows penetration testers to gain access at the same level as insiders, such as company employees. This allows the tester to operate with the same privileges as the insider. An internal penetration test gives the tester the same ability to move around a network as an insider. Testing externally restricts the tester's freedom of movement within the network.

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Blind testing

A blind test only provides a tester with information about the target organization. The purpose of blind testing is to simulate the actions and procedures of a real hacker. An organization's website, domain name, and online discussion board are all publicly accessible sources of information that the pen testing team uses to gather information about the target organization. Testing blind provides inside information about an organization, such as internet access points, directly accessible networks, and confidential or proprietary information that's publicly available.

Double-blind testing

When participating in a double-blind test, an individual has no prior knowledge of the simulated attack. Testing determines how fast and effective the security team is in monitoring and responding to potential attacks and preventing vulnerabilities. Taking this approach may also be of assistance in evaluating the entity's incident identification and response procedures following the detection of a threat.

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White box testing

A white box penetration test involves providing the penetration tester with some information regarding the target network before beginning the test. Information can include details such as internet protocol (IP) addresses, network infrastructure schematics and protocols, and source code. Security professionals may conduct white box testing using an array of methods, both with and without the knowledge of IT personnel. Performing a white box test without the involvement of an organization's IT department may require approval from top management.

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Black box testing

Penetration testing that uses a black box approach aims to identify and exploit vulnerabilities in a system from the outside. A black box penetration test involves omitting information about the target system from security experts before the testing. Black box penetration testing simulates the perspective of a hacker or an end-user when testing an application. It can alert you to serious vulnerabilities in web-facing assets, including validation errors, information disclosure through error messages, and server configuration issues.

Please note that none of the companies, institutions, or organizations mentioned in this article are affiliated with Indeed.

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