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Key takeaways:
- The methodology a penetration testing firm uses determines what they test, how thoroughly they test it, and whether the results are useful for your specific environment. Most founders never ask about it, but they should.
- OWASP is the most widely used framework for web application and API testing, while PTES provides the most comprehensive coverage for broad, multi-surface engagements, and NIST SP 800-115 is the strongest choice for compliance-driven environments with documentation requirements.
- No single methodology is universally superior. The right framework depends on what you're testing.
- Reliable penetration testing firms typically combine frameworks, using OWASP at the application layer and PTES or NIST for process structure and reporting. A firm that rigidly follows only one methodology for every engagement may not be tailoring their approach to your environment.
- Methodology is not a technical detail, but a core part of what you're buying.
When you hire a penetration testing firm, you're not just buying hours of a security professional's time. You're buying a methodology: a structured framework that determines what gets tested, in what sequence, with what level of depth, and how findings get documented.
Two firms can test the same application using different methodologies and produce genuinely incomparable results: one may focus entirely on known vulnerability patterns while the other explores business logic flaws, authentication weaknesses, and chained attack paths that automated frameworks don't detect.
Most founders evaluating pentest providers focus on price, turnaround time, and whether the firm has worked with companies at their stage. And these are important. But the methodology question is also crucial.
This guide covers the four main penetration testing frameworks: what each one covers, when it applies, and what its limitations are. It then addresses the question most founders don't know to ask: how do you evaluate a firm's methodology before you hire them?
Why Methodology Matters?
A penetration test without a structured methodology is effectively an unguided exploration. The tester finds what they happen to look for, documents what they happen to find, and delivers a report whose completeness is entirely dependent on individual skill and intuition rather than systematic coverage.
Methodology solves this by providing a structured sequence of activities: what to assess, in what order, with what documented evidence. That produces repeatable, comparable results. A test conducted under OWASP guidelines will cover a defined set of vulnerability categories, one conducted under PTES will follow a specific lifecycle from pre-engagement through post-exploitation, and one conducted under NIST SP 800-115 will produce documentation aligned to a federal standard.
This matters for startups due to:
Coverage: A methodology defines what's in scope for testing. Without one, significant attack surfaces can be missed simply because the tester didn't happen to look there. With one, the firm can demonstrate that their test systematically addressed the categories of vulnerability relevant to your environment.
Report quality: Methodology determines how findings are documented, categorised, and prioritised. A CVSS-scored finding mapped to a specific framework category is significantly easier to triage, communicate to auditors, and track through remediation than a finding documented in whatever format the tester preferred.
Audit value: If you're conducting a penetration test as part of a compliance program, the methodology affects how useful that evidence is. A report structured around recognised frameworks is easier for auditors to evaluate than an unstructured report of equivalent findings.
For a detailed breakdown of what happens during a penetration test, the five phases from reconnaissance through reporting, check our 5 stages of penetration testing guide.
The Main Penetration Testing Frameworks
OWASP Testing Guide
The Open Web Application Security Project (OWASP) Testing Guide is the most commonly referenced public framework for web application security testing. It's maintained by the OWASP Foundation, a non-profit organisation dedicated to improving software security, and updated regularly to reflect the current threat landscape.
What it covers: The OWASP Testing Guide is organised around the categories of vulnerabilities most relevant to web applications and APIs. These include authentication and session management weaknesses, injection vulnerabilities (SQL, command, and LDAP), access control failures, security misconfiguration, cryptographic weaknesses, and the full OWASP Top 10, the industry's most referenced list of critical web application security risks.
When it applies: OWASP is the appropriate framework when the primary test target is a web application, REST or GraphQL API. For most startups, in which the product is a web-based application with APIs consumed by customers and third-party integrations, OWASP provides the most targeted and relevant coverage.
Limitation: OWASP is explicitly focused on the application layer. It was not designed to cover network infrastructure, cloud configuration, physical security, or social engineering. A test conducted solely under OWASP will not assess your AWS environment, your network segmentation, or whether your employees respond correctly to phishing attempts. If those attack surfaces matter to your security program, OWASP alone is insufficient.
Who uses it: OWASP is referenced by the majority of web application penetration testing firms as their baseline testing standard. It's the framework most commonly cited in proposals for web app and API engagements, and its widespread adoption means findings are documented in a format that most security reviewers recognise.
PTES (Penetration Testing Execution Standard)
PTES is a comprehensive framework covering the full lifecycle of a penetration test engagement, from pre-engagement communication and scoping through post-exploitation and reporting. It was developed collaboratively by security professionals to provide a consistent, end-to-end standard for how penetration tests should be conducted.
What it covers: PTES defines seven phases: pre-engagement interactions (scoping, rules of engagement, and legal agreements), intelligence gathering, threat modelling, vulnerability analysis, exploitation, post-exploitation, and reporting. Unlike OWASP, PTES can be used as an engagement framework for assessments involving physical and social attack vectors.
When it applies: PTES is most appropriate for broad engagements covering multiple attack surfaces, such as: a combined external network and web application assessment, an assessment that includes phishing simulation, or a red team exercise simulating a realistic attacker targeting multiple entry points simultaneously. It provides the most comprehensive lifecycle coverage of any widely used framework.
Limitation: PTES is detailed and comprehensive, but it has not been formally updated since 2012. The core methodology remains sound, but specific technical guidance, particularly around cloud environments, modern API architectures, and AI-related attack surfaces, predates these technologies. Firms using PTES typically supplement it with current threat intelligence and technology-specific testing guidance.
Who uses it: PTES is commonly used by firms conducting broad assessments rather than narrowly scoped web app tests. It's frequently combined with OWASP: PTES for the overall engagement structure and process, and OWASP for application-layer testing within that engagement.
NIST SP 800-115
NIST Special Publication 800-115, Technical Guide to Information Security Testing and Assessment, is published by the National Institute of Standards and Technology. It provides a structured framework for information security testing with a strong emphasis on documentation, process, and auditability.
What it covers: NIST SP 800-115 defines a four-phase process: planning (establishing objectives, rules of engagement, and testing approach), discovery (network and application reconnaissance and vulnerability identification), attack (exploitation and post-exploitation), and reporting (documenting findings, remediation recommendations, and residual risk). The framework places particular emphasis on planning documentation and the reporting phase, both of which are relevant for compliance-driven engagements where the test report needs to serve as auditable evidence.
When it applies: NIST SP 800-115 is the natural choice for US companies in regulated sectors, US government contractors, and companies pursuing alignment with the NIST Cybersecurity Framework (CSF). The framework's documentation requirements produce reports that map cleanly to NIST CSF controls and that federal reviewers are familiar with. It's also a strong choice for any company where the test report needs to function as formal, auditable evidence of security testing.
Limitation: NIST SP 800-115 is less prescriptive than OWASP or PTES at the technical testing level. It defines what should happen but leaves more room for variation in how specific tests are conducted. This makes it a strong process and documentation framework, but firms using it typically supplement with OWASP for application-layer testing and their own technical testing standards for infrastructure.
Who uses it: Penetration testing firms specialising in government, defence, and regulated industries. Also used by firms that prioritise documentation rigour for compliance-driven engagements.
OSSTMM (Open Source Security Testing Methodology Manual)
OSSTMM, published by the Institute for Security and Open Methodologies (ISECOM), is a comprehensive methodology still used in some enterprise and specialised assessments. It covers human security, physical security, wireless, telecommunications, and data networks.
What it covers: OSSTMM is distinctive in its focus on measurable, repeatable testing across all security channels, not just digital ones. It includes specific guidance on physical security testing, social engineering, telecommunications security, and wireless, alongside traditional network and application testing. It also introduces the concept of "attack surface" measurement and a metrics-driven approach to quantifying security posture.
When it applies: OSSTMM is primarily relevant for large enterprise environments where the full range of attack surfaces, including physical access, insider threat, and telecommunications, are in scope. For most early-stage SaaS startups, the physical and telecommunications components are not relevant, making OSSTMM a less targeted choice than OWASP or PTES for typical startup engagements.
Who uses it: Enterprise security assessments, financial institutions, and organisations where physical security and insider threat are significant concerns. Less commonly referenced by firms specialising in startup and SaaS environments.
How to Evaluate a Firm's Methodology
Ask directly: "Which framework do you follow and why?"
A reputable firm can answer this question clearly and specifically. They should be able to name the framework or frameworks they use, explain why those frameworks are appropriate for your environment, and describe how the framework shapes their testing approach and reporting.
Look for framework-environment alignment in the proposal.
A firm that recommends the same methodology for every engagement regardless of what's being tested is not tailoring their approach to your situation.
Verify the methodology in the report structure.
After a test, you can cross-reference the report against the stated methodology: an OWASP-based test should map findings to OWASP categories; and a PTES-based engagement should show evidence of pre-engagement scoping, threat modelling, and post-exploitation assessment. If the report structure doesn't reflect the stated methodology, the firm may be naming a framework they don't actually follow.
Understand that combination is normal.
Most reputable firms combine frameworks. PTES or NIST for overall engagement structure and process, OWASP for application-layer testing within that structure, and current threat intelligence to supplement areas where frameworks haven't kept pace with new technologies. This reflects the reality that no single framework covers all relevant attack surfaces at sufficient technical depth.
Which Methodology Is Right for Your Startup?
Rather than prescribing a universal answer, three scenarios cover most situations.
01. You're testing a web application or API, which is the primary attack surface for most startups: OWASP is the most relevant baseline. It covers the vulnerability categories most likely to affect web-based products, produces findings that most security reviewers recognise, and maps to the types of controls that enterprise buyers check in security questionnaires. A firm combining OWASP with their own API testing standards provides the most targeted coverage for this scenario.
02. You're conducting a broader assessment covering network infrastructure, cloud configuration, and application layer: PTES provides the most comprehensive lifecycle framework for multi-surface engagements. Combined with OWASP at the application layer, it covers the full scope of a typical startup infrastructure assessment. This combination is appropriate for companies preparing for their first serious enterprise sales cycle, preparing for Series B fundraising, or following a security incident that revealed gaps beyond the application layer.
03. You're in a regulated sector, targeting government contracts, or need documentation that maps to NIST CSF: NIST SP 800-115 produces the most auditable, documentation-rich results of any common framework. For US companies targeting government customers or operating in sectors where security testing documentation is reviewed by federal or regulated-industry auditors, NIST SP 800-115 is the appropriate choice. Note that this is a documentation and process standard, and most firms using it will supplement with OWASP or their own technical testing standards at the application layer.
How SecureLeap Approaches Penetration Testing
SecureLeap provides manual, expert-led penetration testing for seed-to-Series B startups, and our testing approach is scoped to your environment.
For web application and API testing, we apply OWASP testing standards as our baseline, supplemented with manual testing for business logic flaws and authentication weaknesses that automated frameworks don't detect. For broader engagements covering network infrastructure and cloud environments, we follow PTES for engagement structure alongside OWASP at the application layer. And for compliance-driven engagements requiring structured documentation, we can align reporting to NIST SP 800-115.
Every engagement includes a clear methodology statement in the proposal: which frameworks we're using, why they fit your environment, and how the report will be structured.
If you want to understand which testing approach fits your current environment and compliance requirements, book a free consultation or send us an email.
Frequently Asked Questions
What is the most widely used penetration testing methodology?
OWASP is the most commonly referenced framework for web application and API testing, the primary attack surface for most B2B SaaS products. PTES is widely used for broader, multi-surface engagements. NIST SP 800-115 is standard in regulated and government environments. Most reputable firms combine elements of multiple frameworks rather than following a single one rigidly.
Does my pentest provider need to follow a specific framework for SOC 2?
No. SOC 2 does not explicitly require penetration testing, and it certainly does not mandate a specific methodology. But if you conduct a pentest as part of your security program, any reputable framework produces a report that can serve as evidence of security control effectiveness. The framework matters more for coverage and quality than for compliance reasons: the question is whether the test was thorough and relevant to your environment, not whether it followed a specific named standard.
What's the difference between OWASP and PTES?
OWASP is focused on the application layer, like web applications, APIs, and mobile backends. It provides detailed, regularly updated guidance on specific vulnerability categories relevant to software products. PTES, on the other hand, is a broader engagement framework covering the full pentest lifecycle across multiple attack surfaces, including network infrastructure, social engineering, and physical security. The two are frequently combined.
Can a firm use multiple methodologies in a single engagement?
Yes, and this is typically a sign of a mature testing approach rather than a lack of discipline. The most common combination is PTES or NIST SP 800-115 for overall engagement structure and reporting, with OWASP applied specifically during the application-layer testing phases.
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