The Full Guide To Penetration Testing

Why Penetration Testing Still Matters In 2025

Attackers keep winning on basics. The Verizon Data Breach Investigations Report 2025 highlights that web application incidents remain heavily driven by credential misuse, with the identity layer central to many breaches. The report emphasizes how stolen credentials dominate common patterns. This puts authentication, session management, and access control front and center for any test plan.

In Europe, ENISA’s 2025 Threat Landscape notes continued pressure from ransomware, hacktivism, and the reuse of known tools. Disruptive attacks and supply chain exposure are rising, which means modern pentests should include third-party and integration surfaces, not only core apps.

Standards bodies still anchor good practice. NIST SP 800-115 remains the foundational playbook for technical security testing, and OWASP ASVS provides concrete control verification targets for web applications. Together, they shape scope, depth, and evidence quality.

Penetration Testing, A Clear Definition

Definition box: A penetration test is a time-boxed, rules-of-engagement based assessment that uses real attack techniques to identify and exploit weaknesses in systems, applications, and people. The goal is to produce actionable findings with evidence, impact, and fixes

Methodologies That Matter

Map your test to industry references

• NIST SP 800-115, use it to structure planning, execution, and post-test activities, including interview driven scoping, rules of engagement, data handling, and reporting.
• OWASP ASVS, use it as a measurable target for web apps, it lists verification requirements for authentication, session, access control, crypto, input validation, API security, and more. Tie your test cases to ASVS controls for traceable coverage.

Practical flow, simplified

1. Scoping and objectives. Define assets, data sensitivity, compliance drivers, test types, and out-of-scope items.
2. Reconnaissance. Enumerate attack surface, third-party integrations, and misconfigurations.
3. Exploitation. Attempt controlled exploitation to demonstrate real risk.
4. Post-exploitation. Prove impact, pivot across roles, validate data exposure.
5. Reporting. Provide evidence, business impact, CWE mapping, and prioritized fixes.
6. Remediation and retest. Validate fixes before closure.

Types Of Penetration Tests

• **Web application testing.** Validate auth, session, access control, input handling, and business logic. Use ASVS mapping for completeness. https://deepstrike.io/services/web-application-penetration-testing-services
• API and mobile testing. Focus on auth flows, JWT and token issues, rate limiting, and data leakage.
• External network. Internet-facing services, DNS, email posture, perimeter misconfigurations.
• Internal network. Assume foothold, test lateral movement, privilege escalation, AD and identity paths.
• Cloud and container security. IAM, storage exposure, CI/CD secrets, Kubernetes misconfigurations.
• Social engineering and phishing, where permitted, to test people and process.
• Compliance driven testing. For PCI DSS 4.0, annual tests and after major changes are expected, with segmentation and application coverage.

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The Pen Test Process, Step By Step

1. Scope and rules of engagement

• Objectives, success criteria, in-scope systems, user roles, test windows, data handling, and escalation paths.
• Define test accounts, MFA handling, and logging expectations for safe execution.

2. Threat-informed planning

• Align test depth with current threats. Identity exploitation, credential reuse, and ransomware staging should shape test cases in 2025.

3. Recon and attack surface mapping

• Asset inventory, subdomains, APIs, third-party widgets, cloud services, and secrets exposure.
• Map findings to ASVS categories to keep coverage honest.

4. Exploitation and post-exploitation

• Prove impact with controlled, reversible actions.
• Validate abuse paths like IDOR, broken access control, SSRF to metadata endpoints, and weak session handling.

5. Reporting that drives fixes

• Evidence with timestamps, requests, and responses.
• CWE reference, severity, affected assets, business impact, and step-by-step remediation.
• Executive summary for non-technical stakeholders.

6. Retesting and closure

• Verify fixes, update the risk register, and capture lessons for secure engineering backlog.

What To Test, A Practical Checklist

• Authentication and session. MFA, password reset flows, token handling, session invalidation on logout.
• Authorization. Vertical and horizontal access control, mass assignment, object reference, tenancy boundaries.
• Input handling. Injection classes, deserialization, template injections, file upload handling.
• Exposure and crypto. TLS, storage encryption, key management, secrets in code and CI.
• Process and logs. Alerting, audit trails, incident response handoffs.
• Business logic. Price manipulation, workflow abuse, race conditions, quota bypass.

Use ASVS to turn this into a measurable control list.

Cost, What Drives The Price

Typical ranges vary by scope and depth. Drivers include number of apps and APIs, user roles, authenticated coverage, cloud complexity, and retest rounds. Compliance needs like PCI segmentation or strict evidence requirements increase effort. Annual programs, or continuous testing, often reduce per-test cost by reusing context and tooling. For regulated apps processing cardholder data, ensure coverage aligns with PCI DSS 4.0 expectations.

How To Choose A Pen Test Vendor

• Methodology and mapping. Ask for alignment to NIST SP 800-115 and OWASP ASVS. Request a sample report.
• Team experience. Look for hands-on app and cloud depth, not tool-only scanning.
• Evidence quality. Clear exploit proof, reproducible steps, practical fixes.
• Retesting policy. Good partners include retests, not just findings.
• Security and ethics. Data handling, logging coordination, and legal controls, as advised in recognized guides.

Compliance, PCI DSS 4.0 Snapshot

• Pen testing is required yearly, and after significant changes.
• Segment cardholder data environment, verify controls, and validate that scoping is correct.
• Document methodology and results for your assessor.

Conclusion

Penetration testing is not a checkbox. It is an evidence-driven practice that lowers real risk when it follows sound methodology, targets current threats, and closes the loop with retesting. Use NIST SP 800-115 for process, map web findings to OWASP ASVS, and align with PCI DSS 4.0 where applicable. In 2025, focus hard on identity and access control, then validate fixes quickly.