Penetration Testing Methodology: Frameworks, Phases & Best Practices

Penetration testing is a systematic security assessment that simulates realistic attacks to identify and validate vulnerabilities and understand their potential impact on an organization. 

A structured penetration testing methodology helps organizations conduct assessments consistently, manage testing risks, and turn technical findings into actionable security improvements. 

• Establish a clear scope and authorization
• Follow a testing process that can be repeated 
• Test realistic attack paths 
• Rely on validated vulnerabilities 
• Gather reliable evidence 
• Figure the impact of technical weaknesses to business
• Provide you with actionable guidance

• Around 12,195 breaches are confirmed from more than 22,000 security incidents in Verizon’s 2025 DBIR.

This detailed guide will explore the major frameworks used for penetration testing, the phases along with the practical implementation of these methodologies in real-world scenarios.

Quick Answer

• Cyber threats are becoming increasingly complex, and a basic security scan may not reveal how attackers could exploit weaknesses in your systems. Penetration testing simulates real-world attacks to uncover vulnerabilities, validate security gaps, and understand their potential business impact.
• Penetration testing is more than running automated tools. Skilled testers examine how vulnerabilities can be exploited or chained together to expose sensitive data, disrupt operations, or gain unauthorized access.
• A structured methodology makes the process more effective. Frameworks such as PTES, NIST SP 800-115, OWASP WSTG, and OSSTMM provide guidance for different testing objectives, environments, and security requirements.
• A typical penetration test follows seven main phases, from defining the scope and gathering intelligence to exploiting vulnerabilities, assessing impact, and reporting findings. Each phase helps ensure that testing is controlled, relevant, and aligned with business objectives.
• Real value lies in knowing which vulnerabilities pose the greatest risk, what needs to be fixed first, and whether remediation has worked. Choosing the right methodology and validating findings through retesting helps turn security testing into actionable decisions.

Major Penetration Testing Methodology Frameworks

Different security engagements require different penetration testing frameworks. The appropriate framework depends on the target environment and testing objectives. 

PTES – Penetration Testing Execution Standard

PTES provides you with a practical end-to-end structure to conduct penetration testing for your organization. It covers all of the following seven major phases of the testing lifecycle: 

1. Pre-Engagement and Scoping
2. Intelligence Gathering
3. Threat Modeling
4. Vulnerability Analysis
5. Exploitation
6. Post-Exploitation
7. Reporting

It provides a structured flow for managing the engagement from planning through reporting.

• Useful for: General penetration tests where teams need a structured lifecycle from planning through final reporting.

NIST SP 800-115

NIST SP 800-115, Technical Guide to Information Security Testing and Assessment, provides guidance for planning and conducting technical security testing and assessments.

Its structured approach is particularly useful when an organization needs a clearly documented assessment process.

NIST helps establish how testing should be: 

• Planned
• Performed
• Analyzed
• Reported

This makes NIST relevant to enterprise security teams that need consistency and traceability throughout an assessment.

• Useful for: Enterprise security assessments where structured testing and documentation are important.

OWASP Web Security Testing Guide

The OWASP Web Security Testing Guide (WSTG) provides detailed testing guidance for web applications, web services, and APIs. Unlike a complete end-to-end penetration testing lifecycle, it focuses more deeply on the technical testing of web technologies.

It covers areas such as:

• Authentication testing
• Authorization and access control
• Session management
• Input validation
• API testing
• Other common web application security controls and weaknesses

When the primary target is a website, web application, or API, WSTG provides detailed guidance for testing web-specific security controls. It helps by combining a broader lifecycle framework such as PTES to provide both engagement structure and detailed web testing coverage.

• Useful for: Websites, web applications, web services, and APIs.

OSSTMM

The Open Source Security Testing Methodology Manual (OSSTMM) takes a broader approach to security testing, focusing on operational security rather than limiting an assessment to a particular technology or application.

It can be useful when your organization needs to examine security across broader operational areas and understand how different components of its environment contribute to overall security.

• Useful for: Broader security assessments that extend beyond a single application or technology.

How These Frameworks Compare

Different testing objectives may require different frameworks or complementary guidance. Based  on the objectives and environment of the engagement, you can use the following combinations. 

Framework	Primary focus	Useful for
PTES	End-to-end pentest lifecycle	General penetration tests
NIST SP 800-115	Technical security assessment	Enterprise/security assessment
OWASP WSTG	Web application testing	Websites, web apps and APIs
OSSTMM	Operational security testing	Broader security assessments

The 7 Phases of Penetration Testing

Penetration testing follows a specified sequence instead of jumping towards scanning and then exploitation. It follows the primary structure of PTES lifecycle. The phases provide a structure for:

• Defining the engagement, 
• Targeting validation 
• Vulnerabilities, 
• Assessing the potential impact 
• Communicating the final results. 

The phases work in a sequence. Skipping any phase directly impacts the quality of testing and the final results. 

Step 1. Pre-Engagement and Scoping

Before the actual testing process, testing teams and  organizations mutually decide what is actually intended to be achieved from the engagement. They mutually decide the following: 

• Objectives of the testing 
• Written Authorization 
• In-scope assets 
• Systems
• Exclusions 
• Rules for engagement
• Approved testing window
• Emergency contacts 

Why it matters:

Setting clear boundaries between the testing team and the organization helps reduce the risk of performing tests on the wrong systems. This prevents the disrupting of the production services and the unauthorized performing activities.

What the tester produces:
Scope documentation, written authorization, and rules of engagement.

Step 2. Intelligence Gathering

Before the exploitation begins, testers get a clear understanding of the target. They identify the following data: 

• Domains 
• Subdomains 
• IP Address 
• Technology 
• Services 
• Elements contributing to the internal and external attack surface of the organization

 The information gathering may involve passive or active reconnaissance. 

• Passive Reconnaissance: Collects data without interacting with the target systems. 
• Active Reconnaissance: Interacts with the target to gather technical details 

Why it matters:
This helps the testers to have a clear understanding about the environment. Better reconnaissance also reveals the overlooked assets which helps with the testing on genuine attack surfaces.

What the tester produces:
An understanding of the target environment, identified assets, technologies, exposed services, and potential entry points.

Step 3. Threat Modeling

The data collected via reconnaissance is used to identify most relevant attack scenarios. The scenarios are designed considering: 

• Critical Assets
• Likely Entry Points 
• Potential Threat Actors 
• Trust Boundaries 
• Business-Critical Systems 
• Possible Attack Paths

Why it matters:
This helps shift the focus from random vulnerabilities to priority scenarios that have the potential of damaging the important systems, data and business operations. 

What the tester produces:
A set of relevant threat scenarios, prioritized attack paths, and testing priorities.

Step 4. Vulnerability Analysis

A combination of automated discovery and manual validation is used to identify potential weaknesses. It may include: 

• Vulnerability Scanning 
• Configuration Review 
• Authentication 
• Authorization Testing 
• Application Testing 
• API Testing 
• Analysis of Security Weaknesses

Manual validation is important because automated tools can produce false positives or miss weaknesses that require context and human analysis.

Why it matters:
FInding the vulnerability and proving it as exploitable may differ. Validation examines whether the vulnerability is actually a genuine attack threat. 

What the tester produces:
Validated vulnerabilities, supporting evidence, affected assets, and an understanding of which weaknesses warrant further exploitation.

Step 5. Exploitation

Validated vulnerabilities go through controlled exploitation to find out if they can actually be used. This also helps figuring the access and the impact they could provide. On the basis of engagement, this also includes validating scenarios like:

• Authentication bypass
• Privilege Escalation 
• Command Execution 
• Access-control Bypass 
• Chaining multiple vulnerabilities 

Why it matters:
This proves the risks with the help of evidence. This is crucial  as it does not simply state that this is a vulnerability, exploitation tells what sort of risk or impact it may create. The exploitation is done at a controlled  pace, without disrupting the environment. 

What the tester produces:
Evidence demonstrating successful or unsuccessful exploitation, the access obtained, and the potential impact of the validated weakness.

Step 6. Post-Exploitation

Post-exploitation activities are authorized. Testers examine what can be achieved realistically after gaining access. This investigation may include: 

• Opportunities for privilege escalation 
• Internal Discovery
• Lateral movement 
• Credential Exposure
• Access to sensitive information 
• Expansion of the attack path

Why it matters:
This helps clearly understand what the attacker could actually access and what could be done with that access. 

What the tester produces:
Evidence of the potential attack path, additional access or exposure identified, and a clearer picture of the potential business impact.

Step 7. Reporting

The reporting phase converts the technical work into actionable findings that can be easily used by stakeholders. Professional testers give you a detailed report that includes both executive view and detailed technical findings.

Executive report covers:

• Major risks
• Business impact
• Key recommendations
• Overall assessment context

Technical report covers:

• Vulnerability
• Affected asset
• Evidence
• Impact
• Risk or severity
• Recommended remediation

Why it matters:

Penetration testing can be useful if the findings can guide the decisions and remediation. Reporting helps connect the technical evidence to the risks different teams require to address. It includes security, engineering and even business teams. After the remediation, retesting can also be performed to figure whether the vulnerabilities have actually been fixed.

What the tester produces:
An executive report, detailed technical findings, remediation guidance, and when requested, a retest report confirming the status of previously identified vulnerabilities.

How to Choose the Right Penetration Testing Methodology

Different methodologies serve different purposes. The right one is determined based on:

• What you are testing 
• Why you are testing it 
• How deep assessment is required

For selection of the right frameworks for your penetration testing process, you need the consider: 

Frameworks	Consider to Question
Target environment	Are you testing a web application, , API, network, cloud environment, or enterprise infrastructure?
Testing objective	Are you identifying vulnerabilities, validating attack paths, assessing controls, or understanding business impact?
Scope	Which systems and assets are authorized for testing?
Required depth	How extensively should each component be assessed?
Compliance requirements	Which regulatory, contractual, or internal requirements apply?
Technology	Which applications, infrastructure, and security controls are involved?

Practical Implementation and Combinations 

Based on different organizational requirements, different combinations of frameworks can be used to gain the maximum output. 

Testing Requirements	Practical Combinations	Impact
APIs or Web Applications	PTES + OWASP WSTG	PTES:  structures the overall engagementWSTG: provides detailed web and API testing guidance.
Enterprise infrastructure	PTES + relevant NIST guidance	PTES: provides the penetration testing lifecycleNIST: supports structured technical assessment and documentation.
Broader operational security	OSSTMM where required	OSSTMM: provides a broader operational security testing perspective.

Key Takeaway

You do not need to strictly stick to one single framework. Different frameworks are used to serve different purposes. 

PTES: For Overall engagement structure

NIST: For structured technical assessment

OWASP WSTG: For in-depth web testing and API testing 

OSSTMM: For broader operational perspective 

The right one is the one that meets your requirements. To fulfill all, you may need combinations that provide you the right structure and do not limit to a single guidance. 

Penetration Testing Methodology Best Practices

A defined methodology provides you with a defined structure for penetration. However, the quality of the engagement may affect depending on how the methodology was practically applied. The following practices help you make your testing process safe, reliable and useful for further decision-making. 

1. Define the Scope Before Testing

• Clarifies targets, exclusions, limitations, and activities before testing even begins. 
• Prevents unauthorized and accidental testing of systems 
• Maintains the focus on the objectives

2. Obtain Written Authorization

• Makes sure the testing never begins without proper authorization
• Obtain written authorization before the engagement begins to protect the organization and the testing team 

3. Combine Automation With Manual Testing

• Automation testing examines large environments at a fast pace and identifies the potential weaknesses. 
• Manual testing helps the testers to validate the complex issues, uncover the logical flows and identify the attack points that automation testing may have missed. 

4. Validate Vulnerabilities

• Testers validate the findings and eliminate the false positives to figure out whether the weakness is valid, relevant and exploitable. 
• This is crucial as scanner findings are not always genuine vulnerabilities. 

5. Demonstrate Business Impact

• Demonstration of the impact is crucial as the findings are useful only if stakeholders can understand the potential attack threat to the business.
• Testers connect the vulnerabilities confirmed by the stakeholders to the potential access, exposure to the data and the rest of the business consequences. 

6. Retest After Remediation

• Risk is not removed entirely simply by fixing the vulnerabilities. 
• The security team goes through the retesting phase to verify whether the remediation works or not. 
• The team is also responsible to figure whether the previous threat is still valid and whether the relevant path for the attack has been addressed. 

Penetration Testing Methodology Example

To see how a penetration testing methodology works in practice, consider a hypothetical e-commerce web application.

The organization wants to determine whether an external attacker could gain unauthorized access to customer information. Instead of immediately scanning and exploiting the application, the testing team works through the methodology step by step.

1. Scope

The organization defines the web application, related APIs, and the systems that are authorized for testing. Testing boundaries, exclusions, and other rules are agreed upon before the engagement begins.

Goal: Make sure testing remains focused on the intended environment.

2. Reconnaissance

Testers examine the application’s externally visible attack surface, identifying relevant endpoints, technologies, APIs, and other exposed components.

Goal: Understand what an external attacker could potentially discover and interact with.

3. Threat Modeling

The team uses this information to identify attack scenarios that could have meaningful consequences for the business.

For this application, priorities might include:

• Account takeover
• Authorization bypass
• Unauthorized access to customer information

Goal: Focus testing on realistic paths to sensitive systems and data.

4. Vulnerability Analysis

Testers assess the application’s security controls, including authentication, authorization, input handling, and APIs. Automated tools may assist with discovery, while manual validation helps determine whether identified weaknesses are genuine and relevant.

Goal: Identify and validate weaknesses that could contribute to the prioritized attack scenarios.

5. Exploitation

Where a vulnerability is confirmed, testers safely validate whether it can actually provide the type of access identified during threat modeling.

Goal: Establish the real-world impact of the weakness without causing unnecessary disruption to the application or its data.

6. Post-Exploitation

If access is obtained within the authorized scope, testers determine how far that access could realistically extend. For example, they may assess whether the compromised position could provide access to sensitive customer information.

Goal: Understand the potential consequences of the initial compromise.

7. Reporting

The findings are documented with the relevant evidence, affected systems, potential impact, risk, and recommended remediation.

The report should make it clear not only what vulnerability was found, but also how it contributed to the broader attack path and why it matters to the organization.

8. Follow-up: Retesting

After the organization implements fixes, testers can return to the affected areas and verify that the original vulnerabilities have been addressed.

Goal: Confirm that the remediation works and that the previously identified attack path is no longer viable.

What This Example Shows

The key point is that penetration testing is not simply a sequence of scans and exploits. Each phase builds context for the next from defining what can be tested to understanding the target, prioritizing realistic threats, validating weaknesses, assessing their potential impact, and verifying remediation.

That structured process is what turns individual technical findings into a meaningful assessment of real-world security risk.

Penetration Testing Methodology Checklist

A structured checklist helps teams confirm that the key stages of a penetration testing engagement have been addressed. It can also serve as a quick reference for security, engineering, and compliance teams before, during, and after testing.

Before testing

• Written authorization
• Scope defined
• Exclusions documented
• Rules of engagement approved

Before testing begins, make sure the engagement has clear authorization and boundaries. This establishes what the testing team is permitted to assess and helps prevent misunderstandings about systems, activities, or testing limitations.

During testing

• Attack surface mapped
• Threats modeled
• Vulnerabilities validated
• Exploitation controlled

Evidence collected

During the assessment, the team should follow the agreed methodology while continuously documenting relevant findings and evidence. This helps ensure that vulnerabilities are validated rather than simply reported based on automated results.

After testing

• Findings prioritized
• Business impact documented
• Remediation provided
• Retesting performed

After testing, the results should be translated into actionable findings. Prioritizing issues, explaining their potential impact, providing remediation guidance, and performing retesting helps organizations move from identifying weaknesses to addressing them.

Use this checklist as a practical quality check for a penetration testing engagement not as a replacement for the methodology itself. The depth and specific activities will vary depending on the organization’s environment, scope, and testing objectives.

Frequently Asked Questions

What are the 7 phases of penetration testing?

The 7 seven phases of penetration testing are:

1. Pre-engagement and scoping 
2. Intelligence Gathering 
3. Threat Modeling 
4. Vulnerability Analysis
5. Exploitation 
6. Post-Exploitation 
7. Reporting 

What is the difference between PTES and NIST?

PTES: Provides a lifecycle with a proper structure from engagement to pre-engagement activities .

NIST SP 800-115: Provide you with a broad guidance for planning, executing, accessing and reporting for the technical security testing and assessments. 

Use PTES for engagement structure and NIST guidance for assessment activities and documentation.

Is OWASP a penetration testing methodology?

OWASP  is a detailed testing framework used for testing web applications  and web services. It provides guidance for:

• Authentication 
• Authorization 
• Session Management 
• Input Validation 
• Business Logic 
• API testing

How is vulnerability scanning different from penetration testing?

Vulnerability scanning uses automated tools to identify potential security weaknesses across systems or applications. Penetration testing goes further by manually validating relevant findings, testing realistic attack paths, and assessing potential impact within an authorized scope. Scanning can therefore be one component of a penetration test, but it does not replace a full assessment.

Does penetration testing include remediation?

Penetration testing identifies and validates security weaknesses and provides remediation instead of fixing the issues itself. After remediation, organizations can request retesting to verify whether the identified vulnerabilities have been addressed and whether the previously demonstrated attack path remains viable.