When most people think of penetration testing, they picture a hooded figure hammering away at a keyboard. The reality is far more structured — and far more effective because of it. A penetration test is only as good as the methodology behind it. Without a proven framework guiding the process, even the most skilled tester risks missing critical vulnerabilities or producing results that can't be meaningfully acted upon.
If you're new to the world of pen testing, our article on the differences between penetration tests and vulnerability scans is a useful starting point. But once you understand what a pen test is, the next question becomes: how should it be conducted? That's where methodologies come in.
A pen testing methodology is a structured, repeatable framework that defines the phases, techniques, and reporting standards for a security engagement. It ensures consistency, thoroughness, and — crucially — that the findings translate into actionable remediation steps. Choosing the right methodology isn't just a technical decision; it directly impacts the quality, scope, and compliance value of your assessment.
In this guide, we'll walk through the most widely recognised pen testing methodologies, explain what sets each one apart, and help you determine which approach best fits your organisation's needs.
Developed by security practitioners for security practitioners, PTES is one of the most widely adopted pen testing frameworks globally. It provides a complete, end-to-end structure for conducting penetration tests that mirror real-world attack scenarios.
PTES breaks the engagement into seven distinct phases:
Best for: Organisations seeking a comprehensive, real-world simulation of how an attacker would target their environment. PTES is particularly strong for infrastructure and network-level assessments where demonstrating actual business impact matters.
Strength: Its practical, hands-on approach means testers aren't just ticking boxes — they're thinking and operating like genuine threat actors. This often uncovers chained vulnerabilities that automated tools alone would miss.
The Open Web Application Security Project (OWASP) needs little introduction in cybersecurity circles. Their Web Security Testing Guide (WSTG) is the definitive resource for web application and API security testing, maintained by a global community of security professionals.
Unlike PTES, the WSTG isn't a full lifecycle methodology. Rather, it's an exhaustive technical checklist covering every category of web application vulnerability — from authentication flaws and session management issues to injection attacks and business logic errors. It aligns closely with the well-known OWASP Top 10, providing specific test cases for each category.
Best for: Any engagement that involves web application or API testing. Most professional pen testing teams use the WSTG as their technical reference during the vulnerability analysis and exploitation phases of a broader methodology like PTES or NIST.
Strength: Unmatched depth for application-layer testing. It's open source, regularly updated, and represents the collective expertise of thousands of security professionals worldwide.
Limitation: It covers web and API technologies only. For a complete pen test, it must be integrated into a broader framework that addresses scoping, reporting, and non-application targets.
Published by the United States National Institute of Standards and Technology, SP 800-115 (Technical Guide to Information Security Testing and Assessment) is the go-to framework for organisations operating in heavily regulated environments or those requiring a formal audit trail.
NIST SP 800-115 structures the testing process into four phases:
Best for: Large enterprises, government bodies, and any organisation where compliance is a primary driver — think PCI DSS, HIPAA, or ISO 27001 environments. The framework's emphasis on documentation makes it ideal where audit requirements are stringent.
Strength: Government-backed credibility and a documentation-heavy approach that satisfies auditors and compliance officers. It provides a clear, defensible record of what was tested, how, and what was found.
Maintained by the Institute for Security and Open Methodologies (ISECOM), OSSTMM takes a fundamentally different approach to pen testing. Rather than focusing on specific technologies or vulnerability types, it's built around the concept of measuring the attack surface — quantifying the actual security posture of an organisation through measurable metrics.
OSSTMM defines testing across five channels: human, physical, wireless, telecommunications, and data networks. This breadth makes it one of the few methodologies that formally incorporates physical security and social engineering into the testing scope.
Best for: Organisations wanting a holistic, metrics-driven view of their security posture across all attack vectors — not just digital ones. It's particularly valuable when you need to benchmark security over time or across multiple business units.
Strength: Its focus on quantifiable metrics (the Risk Assessment Value, or RAV) provides a numerical security score that makes it easier to track improvements and justify security spend to the board.
Limitation: The methodology can feel abstract compared to the hands-on, exploitation-focused approach of PTES. It requires experienced testers to translate its framework into practical testing activities.
The ISSAF, developed by the Open Information Systems Security Group (OISSG), is one of the most comprehensive penetration testing frameworks available. It covers an extraordinarily wide range of assessment areas — from network infrastructure and database security to source code auditing, physical security, and even business continuity planning.
The framework maps specific assessment methodologies to individual security domains, providing detailed technical guidance for each. This makes it an excellent reference for testing teams that need granular, domain-specific instructions.
Best for: Complex, multi-domain assessments where the testing scope extends beyond standard network and application testing. It's also a strong training resource for junior penetration testers building their technical knowledge.
Strength: Exceptional breadth and technical depth across a wide variety of assessment domains.
Limitation: The ISSAF community is no longer actively maintained, which means the framework doesn't reflect the latest threat landscape or modern technologies like cloud-native environments and containerised workloads.
CREST (Council of Registered Ethical Security Testers) isn't a testing methodology in the traditional sense — it's an accreditation body that certifies both individual testers and testing organisations against rigorous professional standards. CREST-accredited assessments follow defined processes that ensure quality, consistency, and ethical conduct.
For organisations in the United Kingdom, Australia, and increasingly across Africa and Asia, CREST accreditation serves as a quality assurance mark. When you engage a CREST-certified provider, you know the assessment will meet internationally recognised standards of professionalism and technical competence.
Best for: Organisations that require assurance of tester quality and ethical standards, or those operating in sectors where CREST certification is a procurement requirement.
While not a pen testing methodology per se, the MITRE ATT&CK framework has become an essential companion to modern penetration testing. It catalogues real-world adversary tactics, techniques, and procedures (TTPs) observed in actual cyber attacks, organised by attack phase.
Increasingly, mature pen testing providers overlay MITRE ATT&CK onto their chosen methodology to ensure testing reflects current, real-world threats rather than theoretical vulnerabilities. This threat-informed approach means your pen test simulates the techniques that actual attackers are using right now — not just the ones listed in a textbook.
Best for: Organisations with a mature security posture looking to validate their defences against specific, known adversary behaviours. It's particularly powerful for red team exercises and advanced persistent threat (APT) simulations.
There is no single "best" pen testing methodology. The right choice depends on several factors specific to your organisation:
In practice, experienced pen testing providers rarely rely on a single methodology. The most effective assessments blend frameworks — using PTES or NIST for the overall engagement lifecycle, OWASP WSTG for application-layer depth, and MITRE ATT&CK for threat relevance.
A penetration test without a sound methodology is little more than an expensive vulnerability scan. The framework guiding the engagement determines whether you receive a generic list of findings or a strategic roadmap for strengthening your defences.
When evaluating pen testing providers, don't just ask what they test — ask how they test. Understanding the methodology behind the assessment helps you evaluate the quality, relevance, and completeness of the results. For a deeper look at making the most of your pen test findings, read our guide on how to interpret and act on penetration testing results effectively.
At Magix, our penetration testing services are grounded in industry-recognised methodologies, tailored to each client's unique environment and risk profile. Whether you need a targeted web application assessment, a full infrastructure pen test, or a comprehensive multi-domain evaluation, our team brings the expertise and structured approach to deliver results you can act on.
Ready to put your defences to the test? Get in touch with our team to discuss the right approach for your organisation.
