Penetration Testing Guide: Types, Process, and Cost

Penetration testing is authorized offensive security work that simulates a real attacker to find and exploit weaknesses in an application, network, or system. A pentest goes beyond listing risks: it attempts real exploits and proves which vulnerabilities an attacker could actually use. The result is evidence of impact, such as a demonstrated data exfiltration or privilege escalation, plus a prioritized fix plan.

Types of penetration testing

Pentests are categorized two ways, and any real engagement combines both.

By knowledge level:

1. Black box: the tester gets no internal information and works like an outside attacker. Realistic, but slow, and it misses reachable bugs the outside view never touches.
2. White box: the tester gets source code, architecture, and credentials. Highest coverage per hour because it can trace real code paths.
3. Gray box: a middle ground with partial knowledge, such as a low-privilege account. A common default for web application work.

By target:

1. Network: external and internal infrastructure, services, and segmentation.
2. Web application: the app layer, including injection, access control, and authentication flaws.
3. Cloud: identity and access misconfiguration, exposed storage, and privilege escalation across cloud roles.
4. LLM application: prompt injection, jailbreaks, and data exfiltration against AI features. This is a fast-growing category covered in the OWASP LLM Top 10 testing guide.

The penetration testing process

Most engagements move through the same phases, whether a human or an agent runs them.

Scoping sets what is in play and what is off limits. Reconnaissance maps the attack surface. Vulnerability analysis forms hypotheses about where the weaknesses are. Exploitation attempts to prove them. Post-exploitation asks how far an attacker could go and whether small findings chain into a serious one. Reporting turns all of it into fixes ranked by real impact.

Cost and cadence

The cost of a manual pentest comes from expert time. At $30,000 to $150,000 per engagement over 2 to 6 weeks, testing tends to happen once or twice a year. That cadence is a problem, because your attack surface changes every time you deploy.

This is why the market has shifted toward testing that runs more often. There are three broad approaches, and they trade off cost against depth.

Manual vs automated vs autonomous

1. Manual: a human expert drives everything. Deepest for business-logic abuse and creative attacks, but expensive and infrequent.
2. Automated: a scanner runs fixed checks and reports matches. Cheap and fast, but it produces probability, not proof, and false positives pile up.
3. Autonomous: AI agents make operator-level decisions, run continuously, and prove each finding. It targets manual-grade accuracy at scanner-grade frequency.

How to choose: if you need a signed report from an independent human assessor for a specific audit, book a manual engagement. If you need broad, cheap coverage on a schedule, a scanner helps. If you want proof-backed findings on every code change without the annual price tag, autonomous testing fits. Many teams run autonomous continuously and add a targeted manual test for the highest-risk features. See autonomous penetration testing for how that works, and Sekura vs manual pentest for a direct comparison.

Where Sekura fits

Sekura is an autonomous penetration testing platform that runs the offensive process end to end. Its 7-phase multi-agent pipeline covers white-box SAST, reconnaissance with 50+ Kali tools, vulnerability analysis with 16 concurrent specialist agents, exploitation with 16 exploit agents that produce evidence-only proofs, cross-validated chain analysis, and reporting with CVSS v3.1, SARIF, and mapping to 14 compliance frameworks. It tests application security, LLM security, and post-quantum crypto in one scan.

Sekura does not replace an independent human assessor when a framework explicitly requires one, and it does not do physical or social engineering. What it does is make broad, proof-first testing continuous instead of annual. It runs in your GitHub Actions runner or fully behind your firewall, and the first scan is free. See pricing or start with npx sekura init.

A pentest is not a checkbox. It is a way to learn how your system actually fails before someone else does.