How to Become a Penetration Tester: Legal Practice, Skills and Certifications

Penetration testing looks like the most exciting job in cybersecurity: getting paid to break into systems. It is exciting. It’s also a job built on documentation, client communication and, above everything, written permission. The difference between a penetration tester and a criminal is authorization.

That’s why this guide starts with the legal side before skills and certifications. You’ll learn what pentesters actually do, the skills to build, where you can practice legally, which certifications employers recognize, and the realistic paths into your first role.

What a penetration tester actually does

A penetration tester (pentester or ethical hacker) is hired to find and safely exploit security weaknesses in an organization’s systems before attackers do, then explain the risk and how to fix it. Typical engagements include:

• Network tests, internal and external, looking for exposed services, weak configurations and paths to sensitive systems
• Web application tests, looking for flaws such as injection, broken access control and authentication problems
• Cloud configuration reviews in AWS, Azure or Google Cloud environments
• Social engineering tests, such as authorized phishing campaigns
• Wireless, mobile app and physical tests for some specialists

A pentest isn’t the same as running a scanner. Our explainer on vulnerability scan vs penetration test covers the difference. A large share of a pentester’s time goes into scoping, careful testing, note-taking and writing a report that executives and engineers can both act on. Strong writers advance quickly in this field.

Start with the law: authorization is everything

In the US, accessing a computer without authorization or exceeding authorized access can be a federal crime under the Computer Fraud and Abuse Act (18 U.S.C. 1030), and states have their own computer crime laws. In May 2022, the Justice Department said federal prosecutors should not charge good-faith security research, but that policy is about prosecution decisions, doesn’t bind states or prevent civil lawsuits, and doesn’t excuse testing systems you’ve been told not to touch.

Practical rules every aspiring pentester should follow:

1. Only test systems you own or have explicit written permission to test.
2. Stay inside the scope. Professional engagements define exactly which systems, dates and techniques are allowed in a signed agreement, often called rules of engagement.
3. For bug bounties, read the program rules and follow them exactly. Out-of-scope testing isn’t protected by the program’s terms.
4. Never test your employer’s, school’s or a friend’s systems “to help” without formal authorization.

This is not legal advice. If you’re unsure whether something is allowed, don’t do it.

Legal places to practice hacking

You can build real skill without breaking any rules. Common options:

A good home lab for beginners includes a Linux attack machine, a Windows server set up as a domain controller, a couple of Windows clients and a few vulnerable apps, all on an isolated virtual network.

The skills to build, in order

Pentesting sits on top of IT fundamentals. Skipping them is the most common reason beginners stall.

1. Networking. TCP/IP, subnets, DNS, HTTP, common ports and protocols, and how traffic flows through firewalls and proxies.
2. Linux and Windows administration. Command line comfort on both, file permissions, services, and especially Windows Active Directory, which shows up in most internal network tests.
3. Web fundamentals. How web apps handle requests, sessions, cookies, APIs and authentication. The OWASP Top 10 is a standard starting point for common web risks.
4. Scripting. Python and Bash or PowerShell for automating tasks and adapting tools. See Python vs JavaScript if you’re choosing a first language.
5. Security tools and methodology. Scanning, enumeration, exploitation, privilege escalation and lateral movement, following a repeatable process.
6. Cloud basics. More environments run in the cloud, so understand identity and access management and common misconfigurations.
7. Report writing and communication. Explain findings, impact and fixes clearly to technical and non-technical readers.

Attackers are also using AI tools, and so are defenders and testers. Our guide on how hackers use AI explains what’s changing.

Key takeaway: The fastest route into penetration testing isn’t collecting hacking tools. It’s solid networking, operating system and web fundamentals, lots of legal hands-on practice, and clear written reports that prove you can explain what you found.

Certifications that help

Certifications matter in pentesting, partly because many clients and contracts ask for certified testers. The most commonly mentioned options:

A few details worth knowing. CompTIA’s PenTest+ V3 (PT0-003) launched on December 17, 2024, requires a 750 on a 100 to 900 scale, and CompTIA recommends 3 to 4 years of hands-on experience plus Network+ and Security+ knowledge. OffSec added the OSCP+ designation for people who pass the OSCP exam from November 1, 2024; OSCP+ expires after 3 years unless renewed, while the original OSCP doesn’t expire.

A sensible order for many people: Security+ for fundamentals, then a hands-on entry cert such as eJPT, then OSCP+ or PenTest+ depending on what employers in your area ask for. Our IT certification decision map helps you plan the sequence.

Realistic paths into your first pentest job

True entry-level pentest jobs are relatively rare. Most pentesters arrive from a nearby role:

• IT support or systems administration, then security, then pentesting. You learn how systems really run. See how to get an entry-level IT job.
• Security operations center (SOC) analyst, then internal red team or pentest work. See how to become a cybersecurity analyst.
• Software development, then application security testing. Developers who understand code make strong web and API testers.
• Junior consultant at a security firm. Some firms hire junior testers with strong certifications and a portfolio.
• Military and government cyber roles, which often provide formal training and clearances.

Pay data: the U.S. Bureau of Labor Statistics doesn’t track pentesters separately. They fall under information security analysts, which had a May 2025 median annual wage of $129,180, with 21% projected employment growth from 2025 to 2035. Entry-level pay is usually lower than the median.

Build a portfolio that proves your skills

Hiring managers want evidence. Build a small portfolio:

• Write-ups of retired lab machines or CTF challenges (only where the platform’s rules allow publishing)
• A sample pentest report for your own home lab, with an executive summary, findings, risk ratings and remediation steps
• Scripts or small tools on GitHub
• Valid bug bounty findings, disclosed only as each program allows

Our guide on how to build a tech portfolio covers presentation.

Where to start this month

1. Set up a home lab with a Linux attack machine and 1 vulnerable target.
2. Review networking fundamentals until you can explain how a web request travels end to end.
3. Complete a beginner learning path on a free or low-cost legal training platform.
4. Write up every machine you complete, even briefly.
5. Pick your first certification and set a target date.
6. Join a local security meetup or CTF team to learn from others and hear about jobs.

Conclusion

Becoming a penetration tester takes solid IT fundamentals, plenty of legal hands-on practice, a recognized certification and the ability to write clear reports. Stay strictly inside authorized environments, build from networking and operating systems up, document everything you learn, and use a nearby role such as IT support, SOC analyst or developer as your bridge into the field.

Sources

• U.S. Department of Justice: New policy for charging cases under the Computer Fraud and Abuse Act — May 2022 policy on good-faith security research
• Justice Manual 9-48.000: Computer Fraud and Abuse Act — federal charging policy text
• CompTIA PenTest+ — PT0-003 launch date, format, passing score, recommended experience and domains
• OffSec: Everything you need to know about the OSCP+ — November 1, 2024 change and 3-year expiry
• OWASP Juice Shop — intentionally vulnerable application for legal practice
• BLS Occupational Outlook Handbook: Information Security Analysts — May 2025 median pay and job outlook