As a CTO, you know that even one small weakness in a web app can cause big problems. Imagine your team launching a new customer portal and everything seems fine until users start reporting suspicious account activity. A quick audit shows the issue wasn’t in the code itself, but in a missing security test that allowed attackers to cause disruption.
In this blog, we will discuss Web application penetration testing methodologies that must be known to tech leaders like you. Below are the three most widely recognized and trusted methodologies used by security teams worldwide.
1. OWASP (Open Web Application Security Project)
OWASP is one of the most respected foundations in web application security, offering a clear framework for testing the strength of a web app. It helps security teams review how the application manages authentication, session handling, access control, and user input validation.
Scope of OWASP: Primarily web applications.
Strengths of OWASP:
- Regularly updated by global security experts.
- Easy to adopt for web app security assessments.
- Provides actionable guidance for developers and testers.
Limitations of OWASP:
- Does not cover network, physical, or human security aspects.
- Focused only on web applications.
Best Use Case of OWASP: Web application penetration testing and secure development practices.
OWASP Core Components
When using OWASP as a penetration testing methodology, three core components guide most of the security assessment: the OWASP Testing Guide, ASVS, and the OWASP Top 10. Each serves a unique purpose and helps testers evaluate different layers of a web application’s security-
A. OWASP Testing Guide
The OWASP Testing Guide is a detailed manual that outlines how to test the security of a web application step-by-step. It covers everything from information gathering and authentication checks to business logic testing and backend validations.
Its biggest strength is its practicality; each security test clearly states what to check, how to perform it, and what results to expect. This makes it a reliable roadmap for penetration testers, ensuring no important security area is missed.
Example Case:
A tester wants to check whether the login page is vulnerable to brute-force attacks. The OWASP Testing Guide provides the exact steps: identify rate-limiting controls, attempt repeated login attempts, observe lockout behavior, and compare the results with the expected secure outcome. This ensures the tester follows a proper process instead of guessing or missing critical details.
B. Application Security Verification Standard (ASVS)
ASVS provides a structured checklist for verifying whether a web application has the right security controls in place. It is organized into different levels (Level 1, Level 2, and Level 3), each representing the depth of security required depending on the sensitivity of the application.
Pentesters use ASVS to validate controls like authentication strength, data protection, input handling, API security, and secure session management. ASVS helps organizations measure their applications consistently and ensures that development teams follow the same security expectations.
C. OWASP Top 10
The OWASP Top 10 is a globally recognized list of the most critical and widespread web application vulnerabilities. It highlights risks such as SQL Injection, Cross-Site Scripting (XSS), Broken Authentication, Insecure Direct Object References (IDOR), and more.
While it is not a full testing framework by itself, the Top 10 acts as a priority guide, ensuring that testers and developers focus first on the attack vectors most commonly exploited in modern breaches. Its regular updates keep security teams aligned with evolving threat patterns.
2. PTES (Penetration Testing Execution Standard)
PTES provides a complete roadmap for conducting a thorough penetration test from start to finish. It divides the process into seven detailed phases:
- Pre-engagement: defining scope and expectations
- Intelligence gathering collecting information about the target
- Threat modeling: understanding potential risks
- Vulnerability analysis: identifying weaknesses
- Exploitation: attempting to break in
- Post-exploitation: assessing what an attacker could do next
- Reporting: documenting findings and remediation steps
What makes PTES valuable is its clarity. Each phase includes practical instructions and suggested tools, helping both testers and organizations follow a consistent and professional process. For companies, PTES sets a baseline standard for what a quality penetration test should include.
- Scope of PTES: Comprehensive penetration testing for networks, systems, and applications.
- Strengths of PTES:
- Clear, step-by-step methodology.
- Includes practical tools and techniques.
- Sets a baseline for professional penetration testing.
- Limitations of PTES:
- Less metric-driven compared to OSSTMM.
- Requires skilled testers for effective execution.
- Best Use Case of PTES: Full-scope penetration testing engagements for organizations.
3. OSSTMM (Open-Source Security Testing Methodology Manual)
OSSTMM focuses on a scientific and measurable approach to security testing. Instead of relying on subjective ratings, it uses structured metrics to evaluate the security level of different operational areas.
OSSTMM covers more than just web applications; it includes network services, wireless channels, physical security, and even human interaction. Key elements such as channel testing, trust analysis, and security metrics help organizations understand their security posture with clear, quantifiable data. This makes OSSTMM especially strong for network penetration testing and broader infrastructure assessments.
Key Elements of OSSTMM:
- Channel Testing: Evaluate communication channels (network, wireless, physical).
- Trust Analysis: Assess trust relationships and dependencies.
- Security Metrics: Quantify security posture with clear data.
- Scope of OSSTMM: Broader than web applications, includes networks, wireless, physical security, and human interaction.
- Strengths of OSSTMM:
- Provides quantifiable results.
- Covers multiple operational areas.
- Ideal for infrastructure and network security assessments.
- Limitations of OSSTMM:
- Complex to implement.
- Requires a deep understanding of methodology.
- Best Use Case of OSSTMM:
Large-scale infrastructure audits and compliance-driven security assessments.
Core Testing Phases for various Web Application Penetration Testing Methodologies
Most penetration testing methodologies, whether OWASP, PTES, or OSSTMM follow a similar sequence of core phases. These phases help testers move from understanding the application to identifying weaknesses, attempting exploitation, and finally reporting the findings. Below is a clear breakdown of each phase and what it involves.
1. Information Gathering / Reconnaissance
This phase focuses on collecting as much publicly accessible information about the target as possible. Testers use tools such as search engines, WHOIS lookups, and subdomain scanners to understand the application’s external footprint.
The goal is to map the application structure, technologies, and potential entry points before deeper testing begins. By understanding how the app is built, its frameworks, APIs, and integrations, testers can pinpoint where vulnerabilities are most likely to appear.
2. Threat Modeling
Once the application architecture is understood, testers analyze which areas pose the highest risk. Threat modeling helps identify:
- Key business assets
- Critical processes
- Potential attacker types
- Their capabilities and motivations
This phase allows testers to prioritize what should be tested in depth. For example, if a financial transaction module handles sensitive payments, it becomes a high-priority target. Threat modeling ensures testing efforts are aligned with real risks, not assumptions.
3. Vulnerability Analysis / Scanning
In this phase, automated tools and manual techniques work together to uncover weaknesses.
Automated scanning: Using tools like OWASP ZAP, Nessus, Burp Suite, and Snyk, testers scan for:
- Outdated components
- Misconfigurations
- Open directories
- Missing security headers
- Known CVEs
Manual analysis: Human pentesters go beyond what scanners detect. They:
- Identify hidden endpoints
- Test how different user roles behave
- Explore API responses
- Look for business logic flaws
- Validate whether scanner findings are exploitable
This combination ensures both surface-level and deep vulnerabilities are discovered.
4. Exploitation
This is where testers attempt to prove that the discovered vulnerabilities can actually be exploited. They begin by simulating an unauthenticated attacker to see what can be accessed without credentials. Then, they use authenticated sessions to test vulnerabilities that require user privileges.
During exploitation, testers may:
- Bypass authentication
- Escalate privileges
- Extract sensitive data
- Execute commands
- Manipulate logic flows
The focus isn’t on causing damage but on demonstrating real-world impact.
5. Post-Exploitation
After a vulnerability is successfully exploited, testers analyze what value the compromised access provides. They try to understand:
- How far the attacker can move within the system
- Whether they can pivot into internal networks
- What sensitive assets can be accessed
- How much control can be gained
This phase highlights the severity of vulnerabilities beyond initial entry—showing the true business impact if a real attacker gained a foothold.
6. Reporting
The final phase documents the entire assessment clearly and professionally.
A complete report includes:
- Executive summary: A non-technical overview for management
- Technical findings: Detailed list of vulnerabilities
- Exploitation methods: How the issues were verified
- Risk ratings: Severity and impact
- Evidence: Screenshots, payloads, and logs
- Remediation recommendations: Exact steps to fix issues
- Methodologies used: OWASP, PTES, OSSTMM, etc.
This ensures both technical teams and decision-makers understand the risks and can take action.
Penetration Testing Methodologies at Peneto Labs
At Peneto Labs, we strictly adhere to globally recognized security testing standards: OWASP, PTES, and OSSTMM to deliver comprehensive and reliable assessments.
Our web application testing aligns with OWASP guidelines, ensuring protection against the most critical vulnerabilities. We follow PTES’s structured seven-phase methodology for penetration testing, guaranteeing a systematic and transparent process from scoping to reporting. Additionally, we incorporate OSSTMM’s scientific, metric-driven approach to provide measurable insights into network, physical, and operational security.
By combining these frameworks, Peneto Labs offers clients a holistic, standards-based security strategy that meets industry best practices and adapts to evolving threats.
Conclusion
As a CTO, understanding the major testing methodologies: OWASP, PTES, and OSSTMM helps you choose the right approach for your security needs. Each framework brings its own strengths, from OWASP’s web-focused guidance to PTES’s structured phases and OSSTMM’s measurable, science-driven techniques. By following these standardized methodologies, organizations gain a clear, repeatable way to uncover vulnerabilities before they turn into real incidents.
At Peneto Labs, we combine these leading methodologies to deliver assessments that are thorough, transparent, and aligned with global best practices.
Don’t wait for a breach to expose vulnerabilities. Let Peneto Labs test, validate, and secure your web applications with precision.