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Penetration Testing [Pen Test]: Types, Methodology & Stages

30th Apr, 2024
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    Penetration Testing [Pen Test]: Types, Methodology & Stages

    You are here to read this article, so we assume you are already aware of the terms “hacking”, “hackers,” and other words associated with unauthorized access. Penetration testing or ethical hacking is the process of attempting to gain access to target resources and perform actual attacks to find loopholes in the system and measure the strength of security. In this article, we will learn about penetration testing, its requirements and understand how real-world ethical hackers perform hacking attacks. 

    What is Penetration Testing? 

    Penetration testing is an approach in which a security expert simulates an attack on a network or computer system to assess its security with the authorization of that system's owners, or we can say, A penetration test (pen test) is an authorized simulated attack performed on a computer system to evaluate its security. Penetration testers use the same tools, techniques, and processes as attackers to find and demonstrate the business impacts of weaknesses in a system.  

    A penetration test works like a real hacker would attempt to breach an organization's systems. The pen testers start by examining and fingerprinting the hosts, ports, and network services associated with the target organization. They will then examine potential susceptible loopholes in the infrastructure of the organization. They will attempt to breach their organization's security perimeter and get entry or accomplish control of their systems. They can examine whether a system is robust enough to withstand attacks from authenticated and unauthenticated positions and a range of system roles. With the right scope, a pen test can dive into any aspect of a system. 

    If We Answer, Who Performs Pen Tests? 

    It’s most suitable to have penetration testing conducted by somebody with little-or-no prior knowledge of how the organization's infrastructure is secured because there is a chance that there are some mistakes or loopholes that might be exposed or missed by the developers who developed the application or built the system. 

    For this reason, only most of the standardized pen test is performed by third-party pen testers. These third-party pen-testers are often called ‘ethical hackers’ as they are hired to hack into a secure infrastructure with permission. 

    These third-party pen-testers could sometimes be experienced developers with fancy degrees and certifications; sometimes, they can be reformed criminal hackers who now use their skills to help improve security, or usually, we have the best ethical hackers who are self-taught.  

    How is a Typical Pen Test Carried Out?

    All kinds of pen tests usually follow some structure or model that contains guidance on how to conduct the whole procedure. 

    If we roughly mention the phases, then we always start with reconnaissance, aka information gathering, where the pen tester spends a significant amount of time gathering data and information about the organization from the active and passive method and try to use that information intelligently to plan their simulated attack. After that, they try to figure out a way to breach into the network or system by exploiting the vulnerabilities, which is known as the gaining access phase, then they focus on maintaining access towards the target by doing privilege escalation or by creating a backdoor. 

    During all of this activity, the certified pen tester uses a broad set of penetration testing tools (pen test tools) to achieve the specific goal, and these tools are typical to use that why learning about them is an essential thing that can be done by joining a quality Cyber Security course which can provide hand-on knowledge over these tools. 

    Different Approaches to Penetration Testing

    There are three different approaches to Penetration Testing, which are as follows: 

    • Black Box Testing
    • White Box Testing
    • Gray Box Testing

    1. Black Box Penetration Testing 

    In a real-world Cyber-attack, the hacker presumably will not be aware of all of the entries and exits of the organization's IT infrastructure. Due to this, the adversary will execute a variety of attacks or use different techniques against the targeted organization, for example, brute force attack against the IT infrastructure, in the expectancies of attempting to find a vulnerability or loophole on which they can take advantage on. 

    Put, from the in this advanced penetration testing methodology perspective of the pen tester in this category of Pen Test; there is no prior information given to the pen tester about the internal details of the respective target, like source code or software architecture or network internal details, or credentials. Because of this, the nature of this attack will consume more time to complete, and sometime the pen tester will depend upon the help of automated approaches to discover flaws and vulnerabilities. This style of a pen test is also referred to as the “trial and error” technique or Opaque box testing. 

    2. White Box Penetration Testing 

    In this type of Pen test, also known as “Clear Box Testing or Transparent box Testing,” in this category of testing, the tester has complete familiarity and access to the source code of the applications and software architecture design of the infrastructure. Because of this nature, a White Box Test can be conducted in a much shorter period in comparison to an Opaque box Test. The additional benefit is that a much more comprehensive Pen Test can be achieved. 

    But this technique also has its drawbacks. As the tester has a full understanding of the infrastructure, it could take more time to determine what to concentrate on, particularly in terms of testing the organization's infrastructure. Additionally, to perform White box penetration testing, more sophisticated penetration testing tools are needed. 

    3. Gray Box Penetration Testing 

    As the name suggests, this category of Penetration testing is a blend of the White Box Test and Black Box. Over here, the penetration tester only has a partial understanding of the internal infrastructure of the organization. 

    In the Gray Box Test (aka Semi-opaque box), both manual and automated testing methods can be employed. In this approach, a pen tester can concentrate on their immediate actions and focus on those areas of the infrastructure which they understand the most. With this method, there is a more elevated chance that more difficult-to-find “security loopholes” will be discovered by the pen tester. 

    All these methodologies are being taught in one of the best CEH courses, where industry experts give guidance on how these methods work in real life. 

    What are the Categories of Pen Tests? 

    There are various elements in the organizations that need to be tested and have their parameters to check the security posture. 

    Similarly, in cyber security, we have several specialization sectors which focus on each element that how to check or pen test each sector. One cybersecurity individual can be an expert in one or more domains. 

    Here is the list of some of them which can be considered the primary sectors or penetration testing types required by the industry: 

    1. Web apps

    Web application penetration testing is one of the most dynamic and most visible areas of any organization, Pen Testers review the persuasiveness of security controls in place and look for hidden vulnerabilities through automotive or manual testing procedures, look for logical attack patterns that can go undetected by tools, and any other potential security gaps that can lead to a compromise or a breach of a web application or it is data. 

    2. Mobile apps

    Mobile applications are also a major component of today's industry; Pen testers look for vulnerabilities using automated and advanced manual testing in application binaries running on the mobile device, its source code, the transmission mode of data, and the related server-side functionality. That can include a variety of tests like handling session management, Weak or other cryptographic issues, Business logic or authentication and authorization issues, and other common vulnerabilities. 

    3. Networks

    At the current time, Network pen testing is necessary for every business because threats could be anywhere inside or near the organization's infrastructure. Network pen testing identifies common and critical security vulnerabilities in an internal & external network used by organizations. Professionals operate a checklist that comprises test cases for numerous issues like Host identification, encrypted transport protocols, and more. 

    4. Cloud

    Clouds provide great advantages and endless facilities to any business today, and that is why no organization resists shifting to a cloud environment. This is also true that the cloud environment is quite different from the traditional on-premises infrastructure. Generally, security responsibilities are shared between the Cloud customer (organization) using the environment and the cloud services provider, aka the shared responsibility model. Because of this, cloud pen testing demands specialized skills and experience to analyze the diverse elements of the cloud, such as encryption, configurations, databases, APIs, storage, and other security controls. 

    5. APIs

    For every test, we have some standard or non-standard curated models of frameworks that help every tester to plan the whole journey from beginning to end. For example, here, automated and manual testing procedures are covered under the testing methodology guide starting from the OWASP named OWASP API Security Top 10 list. Which allows the testers to look deeper and in a planned way to assess various vulnerabilities, including broken object-level authorization, rate limiting, user authentication/authorization, data exposure, and more. 

    6. Containers

    Containers are another buzzing tech obtained from Docker and often contain vulnerabilities that can be exploited at scale to cause damage. Misconfiguration is one of the common risks associated with containers and their running environment. These kinds of risks can be discovered by a professional pen tester. 

    7. Embedded devices (IoT)

    IoT devices are becoming a major component in many industries, including the healthcare, Oil & Gas Industry, Power sector, automobiles, etc. 

    These embedded devices are also being used for multiple purposes, including in-home appliances, watches, etc. They have specific software testing conditions due to their more extended life process, remote locations like sensors over unreachable areas, power grids, and more. Professionals conduct a detailed analysis on both sides of the client and server to identify weaknesses that matter most to the applicable situation. 

    8. CI/CD pipeline

    Modern DevSecOps practices incorporate automated and smart, and secure code analysis tools into the CI/CD pipeline. Along with static tools that discover known vulnerabilities, automated pen testing tools and techniques can also be incorporated pipeline to simulate what a real-life hacker can do to compromise security. Automated pen testing can uncover hidden vulnerabilities that can go undetected with static analysis and vice versa. 

    Penetration Testing Stages/Phases

    There are several ways in the industry that can be followed up and can help the organization build up the penetration strategy based on the requirements as there is no single model internationally holding accreditation as a standard penetration testing model or framework so we have various frameworks coming from different organizations of the infosec community that can be modified as per their needs. 

    Some of the penetration testing examples of methodology selection a more: 

    1. OSSTMM

    The OSSTMM framework, one of the standards globally recognized in the industry, delivers a research-based methodology for vulnerability assessment and specifically for network penetration testing. 

    2. OWASP

    This modal is an overall package for all issues of application security; the Open Web Application Security Project (OWASP) is the most acknowledged standard in the industry. 

    3. NIST

    Unlike other information security frameworks and manuals, NIST suggests more detailed guidelines for penetration testers to follow. 

    4. PTES

    The PTES Framework (Penetration Testing Methodologies and Standards) emphasizes the most instructed procedure to structure a penetration test. 

    And many more penetration testing frameworks are present. Let us take one and explore the penetration testing phases and stages it contains. 

    Dive into PTES Framework 

    In PTES Framework (Penetration Testing Methodologies and Standards) Model, we have seven phases or steps named and sequenced as follows: 

    1. Phase one: Pre-engagement Interactions 

    This phase contains intense and multiple meetings with the clients to discuss how all things will take place. 

    For instance, questions like: 

    • Why is the client having the penetration test conducted against their environment? 
    • Is the penetration test needed for a particular compliance requirement? 
    • How many total IP addresses will be tested? 
    • How many web applications will be assessed? 
    • etc. etc. 

    2. Phase two: Intelligence Gathering 

    Then in this phase, we perform Intelligence information Gathering, and this information and data will be used in later phases when penetration will be done on the target while conducting vulnerability assessment and exploitation. 

    3. Phase three: Threat Modeling  

    This section defines a threat modeling approach as required for the correct execution of penetration testing. 

    For example, we make the high-level threat modeling approach: 

    • Gather appropriate documentation.
    • Recognize and classify primary and secondary assets.
    • Recognize and classify threats and threat neighborhoods.
    • Map threat neighborhoods against direct and secondary assets.
    • etc. 

    4. Phase four: Vulnerability Analysis 

    Over here, in this phase, we do vulnerability assessment penetration testing, which is the procedure of uncovering weaknesses in systems, applications, and networks that can be leveraged by an adversary. These weaknesses could be anything ranging anywhere from the system, network, service, misconfiguration, or insecure application design.

    While performing vulnerability analysis of any type of pen testing, the pen tester should properly take care of and focus on the scope of the testing for appropriate depth to meet the requirements of the contract and organization.

    5. Phase five: Exploitation 

    The exploitation phase of a penetration test concentrates exclusively on establishing access to a system or any resource by circumventing security rules. If the previous phase vulnerability analysis was conducted correctly, this phase should be well prepared and an exactitude walkout. The main priority is to recognize the entrance point into the infrastructure of the organization and to determine high-value assets.

    6. Phase six: Post Exploitation 

    This phase is also critical, and as the name suggests, the purpose of the post-Exploitation phase is to determine the importance of the machine or data compromised and to maintain access to the target machine for future use. The importance of the machine is determined by the sensitivity of the data stored on it and how it values the organization.

    7. Phase seven: Reporting 

    This is the important phase as this will contain all the findings discovered in the previous phases and help the organization to understand the criticalness and other things present in their infrastructure and how it can impact the organization if an attacker is successfully able to compromise the vulnerability.

    Top 10 Tools for Penetration Testing

    Tools play a significant role in penetration testing. These tools help to identify security weaknesses in the network, server, hardware, and application. Penetration tools are nothing but software applications that are developed to check loopholes that the actual hacker us.  However, the same tools are also used by pen testers to check the threats that may compromise the security of the organization. This is like a weapon that can kill but can also protect from enemies.

    There are hundreds of penetration testing software available in the market to perform various penetration testing operations. We will look at some of the most common tools used for penetration testing, which are helpful for common testing features and are widely accepted by most organizations.

    1. Metasploit

    Metasploit is a widely used penetration testing tool framework. Using Metasploit, testing teams can verify and manage security assessments that keep white hat hackers a step ahead.

    Metasploit has a user-friendly GUI interface along with a command line. It also supports all operating systems like Mac OS, Linux and Windows, But it’s more commonly run-on Linux. Metasploit allows testers to break into the system and identify severe flaws. Testers can exploit the flaws and perform actual attacks with this tool. Metasploit provides more than 1500 exploits using metadata.

    2. Wireshark

    Wireshark is the world's most widely used network protocol analyzer. This tool helps testers to check what is happening on the network at a microscopic level. Wireshark helps with the deep inspection of hundreds of protocols along with living captures and offline analysis features. Wireshark also supports all major OS like Windows, Linux, MacOS, Solaris etc.

    Powerful display filters, rich VoIP analysis, coloring rules, decryption ability and many other features make Wireshark an unbeatable industry leader in the market.

    3. BeEF

    BeEF stands for Browser Exploitation Framework. This penetration testing tool is used to check a web browser and explore weaknesses in the client system and network. It also looks past hardened network parameters and client systems.

    It can use more than one browser for launching directed command modules and further attacks in the context of the browsers.

    4. Burp suite

    Burp suit is ideal for testing web-based applications.  Burp Suite is widely used by most information security professionals.

    This framework uses web-based penetration testing on the JAVA platform with automatic crawling capacity over the application. It has features to map the tack surface and analyze requests between a browser and destination servers.

    5. Nessus

    For 20 years, 30000 companies have been using Nessus tools for their penetration testing process. This is the most powerful tool in the world, with more than 45000 CES (Cyber Exposure Score) and 100000 plus plugins for scanning IP addresses and websites and completing sensitive data searches. Using Nessus, testers can locate the weak points in the systems.

    Nessus can be helpful for locating and identifying missing patches and malware, including all operating systems, applications, and mobile scanning. A fully featured dashboard, wide scanning capacity and multi-format report facility make Nessus the best tool for VAPT worldwide.

    6. Nmap

    Free, flexible, powerful, portable, and easy to use, Nmap is an open-source network discovery and security auditing tool.

    Nmap is useful for checking and managing service upgrade schedules, monitoring hosts and running services with uptime, network inventory management etc. It uses raw IP packets to determine whether hosts are available or not. Nmap also helps to check what services are running hosts along with application name, version, and operating system details. Testers can check what type of packet filters are in use. Nmap has the ability to scan a single system to large networks. It supports most of the operating systems.

    Nmap is so popular that it has been featured in 12 movies, including The Matrix, Snowden, Ocean’s 8, Die Hard 4, Girl with the Dragon Tattoo etc.

    7. Aircrack

    Aircrack NG is the tool for the assessment of wireless security. Aircrack can monitor captured packets and transfer data to the text file, which can help third-party tools for monitoring processes. Using Aircrack, pen testers can crack WEP and WPA protocols. The CLI interface of Aircrack allows heavy scripting yet also supports GUIs and operating systems like Windows, OSx etc.

    8. SQLmap

    SQLmap is a tool to automate the process of detection and exploitation of SQL injection flaws in the application and database servers. SQLmap comes with a powerful detection engine that supports all database management systems.  It supports all six SQL injection techniques like Boolean-based blind, time-based blind, error-based, Union based etc.

    By providing proper authentication, IP address, port and database name, it can bypass SQL injection and connect with the database.

    9. OWASP Zed Attack Proxy (ZAP)

    ZAP is a free, open-source penetration testing tool for testing web applications. It is also known as “man in the middle proxy” because it stands between the tester’s browser and the web application so that it can intercept messages, modify them if required and send them to the destination. It supports all major OSs and Docker.

    It can also construct a map of the application and record the requests and responses and generate alerts if something is wrong.

    10. SET - Social Engineering Toolkit

    SET (Social engineering toolkit) is an open-source penetration testing framework designed to perform social engineering attacks. It is designed to perform a human-side penetration test to check if any human error can convert into a threat for the organization.

    SET has several custom attack vectors in which targets can get trapped easily.  SET can be integrated with the Metasploit framework. Using SET penetration, testers can perform Phishing attacks, website attacks, malware attacks, create payload and eavesdropping, mass mailing etc.

    These are the basic and common tools used by penetration testers or white hat hackers to find out major weaknesses in the systems or network. There are more than 300 tools available on specialized OS for penetration testing like Kali Linux, Parrot Security Operating system, Backbox, DEFT, Samurai Web testing framework, Node Zero etc.

    What are the Benefits of Penetration Testing?

    Penetration tests are a practice of simulating a variety of attacks that could be a threat to a business. By doing consistent pen testing, businesses can acquire professional and unbiased third-party feedback on their security posture. But it is potentially time-consuming and expensive; pen testing can help prevent extremely expensive and harmful breaches.

    Here are some of the mentions: 

    1. Identify and Classify Threats

    The periodic web application penetration testing can help the organization to examine and assess web applications and internal and external network security for any threat that exists and prioritize it.

    Prioritizing these threats provides organizations with an advantage in predicting threats and controlling potential malicious attacks from happening.

    It also helps to understand what security controls are necessary to have to maintain the security of the organization's people and assets.

    2. Control Adversaries from Penetrating Infrastructure

    Penetration testing is like real-life hacking performed by a real-life hacker. Performing periodic or regular penetration tests authorizes you to be aggressive in your real-world security approach to assessing your IT infrastructure security.

    The method uncovers security gaps or loopholes in your security, offering you the possibility to appropriately remediate any faults before an actual adversary action arises.

    3. Regular Upgrades in your Security Environment

    Continuing to upgrade the security posture within the infrastructure of your organization’s environment is a main method to maintain a competitive edge against other organizations or adversaries in the industry.

    4. Avoid Expensive Data Breaches that Cost Reputation

    Recovering from a data breach is no doubt expensive in cost as well as reputation. Legal expenses, IT security remediation, customer safety, loss of trust, and dejected customers can cost businesses more than millions of bucks.

    According to the IBM report, the cost of a data breach average cost increased 2.6% from USD 4.24 million in 2021 to USD 4.35 million in 2022. Regularly planned penetration tests are a creative way to stay ahead of your security and can help control or prevent the monetary loss of a breach, along with guarding your brand and reputation.

    5. Support Compliance with Data Privacy and Industry Security Regulations

    Penetration tests help the organization comply with the compliance and security responsibilities that are demanded by industry standards and regulations such as PCI DSS, HIPAA, GDPR, FISMA, etc.

    Having these compliance tests performed regularly along with pen tests helps to present your commitment to information security, all the while assisting you to dodge the hefty penalties that can be associated with non-compliance.

    What are the Pros and Cons of Pen Testing?

    Let's divide the Pros and cons into two contexts of Manual and automated Penetration Testing:

    A) Pros and cons of Manual Penetration Testing


    • Assures that the application is comprehensively pen-tested.
    • Tests the infrastructure in-depth with various tools and techniques.
    • It is commonly considered an important phase for a comprehensive security assessment.


    • This provides a slow pace the progress while the organization waits for the outcomes.
    • Sometimes this process can be too expensive to conduct a test on all the components held by the infrastructure of the organization.
    • Sometimes it leaves security gaps between tests as some areas could go missing.

    B) Pros and cons of Automated Penetration Testing


    • Not too pricey if we talk about per scan by an automated tool.
    • Scans on demand are present and can be used in various stages of security assessment and expansion of the organization.
    • A good visual and updated benchmark shows how much progress has been made over the selected period.


    • It is not considered to be adequate, particularly if accomplished with an on-premises tool.
    • Only capable of scrutinizing the test cases that security tool vendors provide as a part of the scanner.
    • Have more potential to generate false positives and false negatives results.


    This article delivered a comprehensive overview of what Pen Testing is, its types, stages, and how it is done, along with the cyber security penetration testing techniques which are involved. We dive into the PTES framework to understand the process and method of pen testing from a closer view. In closing, this is how the hackers will make the attack, and the defensive side will try to protect the organizations and prepare before hackers to uncover all the possible threats by conducting pen tests and exploiting them wherever possible to know the impact.

    Frequently Asked Questions (FAQs)

    1. Which is best used for penetration testing?

    The use of the pen testing process is always to stay ahead of the adversaries and protect the organization from getting attacked.

    2. What is the difference between a penetration test and a security test?

    Security testing is a process of scanning the organization's network, including the physical environment too, for the existing risks and vulnerabilities that can lead to compromise and help an attacker steal data and cause harm to the organization. 

    On the other hand, Penetration testing is a more sophisticated process and a type of security testing that focuses on discovering the vulnerabilities and exploiting them to know how they can impact the organization's infrastructure and even how to fix them sometimes.

    3. Is penetration testing difficult?

    Yes, Penetration testing is a complicated process and critical process. If it is not done carefully with the right expertise, it can bring down the organization's business or can cause data breaches. So, it requires a lot of effort to learn and gain expertise in this domain. To provide this kind of expertise, we provide KnowledgeHut’s Cyber Security certifications in cyber security where learners can learn how to secure an organization from threats by performing penetration testing.

    4. How much do penetration testers earn?

    The earnings always depend on the person's skill set, but if we look at statistics, then you find, and I'll quote the statement of PayScale "As of September 2021, pay scale reported a typical base salary of nearly $87,000 per year for pen testers. At the low end (bottom 10%), pen testers earn about $59,000 per year. At the high end (top 10%), they make up to $138,000 per year."

    5. What is a penetration Test checklist?

    You can consider the penetration Test checklist as a guideline that will provide the pen tester guidance on how to conduct a pen test and emphasize the tests that have to be done against the target infrastructure. It will help the pen tester not to lose track and miss any test that has to be done.


    Vitesh Sharma

    Blog Author

    Vitesh Sharma, a distinguished Cyber Security expert with a wealth of experience exceeding 6 years in the Telecom & Networking Industry. Armed with a CCIE and CISA certification, Vitesh possesses expertise in MPLS, Wi-Fi Planning & Designing, High Availability, QoS, IPv6, and IP KPIs. With a robust background in evaluating and optimizing MPLS security for telecom giants, Vitesh has been instrumental in driving large service provider engagements, emphasizing planning, designing, assessment, and optimization. His experience spans prestigious organizations like Barclays, Protiviti, EY, PwC India, Tata Consultancy Services, and more. With a unique blend of technical prowess and management acumen, Vitesh remains at the forefront of ensuring secure and efficient networking solutions, solidifying his position as a notable figure in the cybersecurity landscape.

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