Getting Started in Penetration Testing: A Beginner’s Guide to Hands-On Experience – Testkings

Penetration testing, often referred to as pen testing or ethical hacking, is the process of simulating cyberattacks against a system, application, or network to uncover vulnerabilities that could be exploited by malicious hackers. Unlike standard security assessments, penetration testing actively attempts to exploit weaknesses, providing a more realistic view of how vulnerable a system truly is under attack conditions.

The primary goal of penetration testing is to identify security flaws before malicious actors can discover and exploit them. This proactive approach helps organizations stay ahead of threats by closing security gaps, strengthening defenses, and validating the effectiveness of current security measures. Penetration testing is not just about finding vulnerabilities—it also evaluates the potential business impact if those vulnerabilities were exploited, helping prioritize remediation efforts.

Penetration tests are generally performed by security experts or ethical hackers who are authorized to simulate real attacks. These experts use the same tools and tactics as cybercriminals, including phishing, brute force attacks, SQL injections, and privilege escalation techniques. However, they do so in a controlled environment with clear scope definitions and safeguards to avoid damaging systems or data.

There are different types of penetration testing, each tailored to specific areas of concern. Network penetration testing focuses on discovering weaknesses in internal or external network infrastructure. Web application testing evaluates the security of websites and APIs, looking for common flaws like cross-site scripting (XSS) or insecure authentication. Wireless testing targets Wi-Fi networks, while social engineering tests assess human susceptibility to manipulation, such as phishing attacks. Physical penetration testing, although less common, examines how easily an unauthorized person could gain access to physical locations or sensitive assets.

The importance of penetration testing has grown significantly as cyberattacks have become more sophisticated and frequent. Regulatory standards such as PCI-DSS, HIPAA, and ISO/IEC 27001 often require regular penetration tests to ensure compliance. In many industries, periodic testing is not just a best practice—it is a legal or contractual necessity. For example, companies handling credit card transactions must undergo regular testing to remain PCI-DSS compliant.

Penetration testing also plays a vital role in risk management. By identifying which systems or data are most vulnerable and understanding the extent of potential exploitation, organizations can allocate resources more effectively. Instead of spending money on blanket solutions, businesses can take targeted actions to protect their most critical assets.

Moreover, penetration testing supports the development of a mature security culture within organizations. When security teams, developers, and management see firsthand how easily a system can be breached, it often leads to more serious investment in security controls and better adherence to security policies. It also helps technical teams stay current with emerging threats and the latest defense mechanisms.

However, penetration testing is not a one-time activity. As systems evolve and threats change, continuous or periodic testing is essential. New software deployments, infrastructure changes, and even personnel shifts can introduce vulnerabilities. Regular testing ensures that security remains strong in the face of these dynamic changes.

In conclusion, penetration testing is a critical part of any robust cybersecurity strategy. It provides a real-world assessment of security defenses, exposes hidden vulnerabilities, and delivers actionable insights for improvement. Whether mandated by regulations or implemented as a best practice, penetration testing empowers organizations to detect and mitigate risks before attackers can cause harm.

Core Concepts and Tools in Penetration Testing

Penetration testing, or ethical hacking, is a complex field that demands a deep understanding of how systems work, how they fail, and how to detect and exploit those failures in a controlled and legal environment. This part explores the key concepts that underpin professional penetration testing and the essential tools that allow ethical hackers to carry out their work effectively. Whether you are preparing to practice in a lab or perform your first real-world engagement, understanding this core knowledge is a non-negotiable first step.

The Structure of a Penetration Test: Standard Phases

All professional penetration tests follow a methodological structure, typically divided into five key phases. These steps guide the tester from initial research all the way to actionable reporting. Understanding each phase ensures that tests are efficient, repeatable, and legally sound.

1. Reconnaissance (Information Gathering)

Also known as “footprinting,” reconnaissance is the initial stage in which the tester gathers as much intelligence as possible about the target. This process can be divided into passive and active reconnaissance.

Passive reconnaissance involves collecting data without directly interacting with the target system. This can include scouring websites, social media, domain registration records (via WHOIS), DNS data, and even job postings or leaked documents to find information about the target’s technology stack, employee names, IP ranges, and more.

Active reconnaissance involves probing the target environment more directly, such as performing ping sweeps, traceroutes, or basic port scans. This step is more likely to be detected but reveals more in-depth information.

2. Scanning and Enumeration

Once basic intelligence has been gathered, the next phase is scanning and enumeration. Scanning helps identify live hosts, open ports, and active services. Enumeration involves more detailed interaction with those services to extract system information, user accounts, network shares, or software versions.

Common tools used during this phase include:

Nmap: Network mapping tool that provides insight into hosts and services.
Netcat: Often used to read and write data across network connections.
Nessus or OpenVAS: Vulnerability scanners that compare known system versions and configurations with databases of common exploits.
Enum4linux: Gathers detailed info from Windows machines using SMB protocols.

At the end of this stage, testers usually have a strong profile of potential attack vectors and are ready to move into the exploitation phase.

3. Gaining Access (Exploitation)

This is the most well-known phase of penetration testing, where ethical hackers attempt to exploit discovered vulnerabilities to gain unauthorized access. This could involve exploiting a misconfigured database, an outdated web application, or a weak network protocol.

Metasploit is often used in this phase because it contains a large database of known exploits and payloads. However, effective exploitation also requires scripting knowledge, creativity, and strong debugging skills. Testers must often combine multiple low-severity vulnerabilities into a full-blown attack chain.

Key techniques used in this phase include:

SQL injection attacks
Cross-site scripting (XSS)
Remote code execution
Buffer overflows
Exploiting default credentials
Command injection

4. Maintaining Access and Post-Exploitation

Once access is obtained, the tester will explore how deeply they can embed themselves within the network. This is important because it simulates what a real attacker might do once inside.

This step often involves privilege escalation, creating persistence (like installing a backdoor), or moving laterally within the network to access more systems. The goal is to understand the extent of access an attacker could obtain and to test the organization’s detection capabilities.

Post-exploitation also involves harvesting credentials, locating sensitive files, and determining the value of the compromised data. It answers questions such as: “What could an attacker do next?” and “How long could they remain undetected?”

5. Reporting

Perhaps the most important (yet often underestimated) phase is reporting. All findings must be documented clearly and concisely, explaining the vulnerabilities discovered, how they were exploited, the potential business impact, and how to remediate them.

A good penetration test report includes:

Executive summary
List of discovered vulnerabilities
Proof-of-concept screenshots or logs
Risk ratings
Remediation recommendations

The ability to translate technical findings into business risk is what sets professional penetration testers apart from amateurs.

Essential Penetration Testing Tools

Penetration testing relies heavily on tools, both open-source and commercial. While tools do not replace knowledge or strategy, they allow testers to perform comprehensive testing efficiently. Below are some of the most widely used categories and their respective tools.

Network Scanning Tools

Nmap: Versatile for scanning open ports, detecting services, OS fingerprinting, and running NSE scripts.
Angry IP Scanner: A fast scanner for finding live hosts on a network.
Masscan: Extremely fast port scanner for wide IP ranges.

Vulnerability Scanners

Nessus: Offers a broad range of vulnerability checks across systems and applications.
OpenVAS: A free alternative to Nessus that performs similar scans.
Nikto: Scans web servers for insecure files, outdated software, and configuration issues.

Exploitation Frameworks

Metasploit Framework: Core tool for exploiting vulnerabilities, creating payloads, and performing post-exploitation.
BeEF (Browser Exploitation Framework): Targets vulnerabilities in web browsers.
SQLmap: Automated tool for SQL injection and database takeover.

Web Application Testing Tools

Burp Suite: Industry-standard tool for intercepting and modifying HTTP requests/responses.
OWASP ZAP: Open-source tool for detecting common web vulnerabilities.
Wfuzz and Dirbuster: Brute-force tools for discovering hidden files and directories.

Wireless Testing Tools

Aircrack-ng: Suite for analyzing and cracking WEP and WPA-PSK keys.
Reaver: Brute-forces WPS pins to retrieve WPA2 keys.
Kismet: A passive wireless network detector and sniffer.

Password Cracking Tools

John the Ripper: Cracks password hashes using dictionary, brute-force, and rule-based attacks.
Hashcat: Known for GPU acceleration, used for high-speed hash cracking.
Hydra: Fast network logon cracker supporting multiple protocols.

Post-Exploitation Tools

Mimikatz: Extracts credentials from Windows memory.
Empire: A post-exploitation agent written in PowerShell and Python.
BloodHound: Visualizes Active Directory relationships to uncover privilege escalation paths.

Common Testing Approaches: Black, White, and Gray Box

Depending on the scenario and what information is shared with the tester, penetration testing engagements can be categorized into three types:

Black Box Testing: The tester starts with no prior knowledge about the systems. This simulates an external attacker. It’s realistic but time-consuming.
White Box Testing: The tester has full knowledge of the system, including source code, credentials, and infrastructure diagrams. It’s more efficient but less reflective of real-world conditions.
Gray Box Testing: A mix of both. The tester is given partial information. This simulates an insider threat or an attacker with limited access.

Choosing the right approach depends on the organization’s goals. For example, black box is excellent for testing perimeter security, while white box is better for identifying internal application flaws.

Common Targets and Vulnerabilities

The most commonly tested areas in penetration tests include:

Web applications: prone to injection flaws, broken authentication, and misconfigured security headers.
Internal networks: often vulnerable to credential reuse, lack of segmentation, or outdated services.
Wireless networks: misconfigured encryption or rogue access points.
Mobile applications and APIs: may leak sensitive data or fail to implement proper access control.
IoT devices: often lack basic security controls and use hardcoded credentials.

Some of the most well-known vulnerabilities are categorized in the OWASP Top Ten for web apps, such as SQL injection, cross-site scripting (XSS), and broken access control.

Legal and Ethical Boundaries in Penetration Testing

One of the most important concepts every aspiring penetration tester must grasp is the legal and ethical framework in which they operate. Ethical hacking is only legal when done with explicit permission. Penetration tests without consent are illegal and can lead to criminal prosecution.

Every engagement must include a written agreement that defines:

Scope (which systems and IP ranges can be tested)
Time frame
Types of tests allowed
Contact points in case of emergency
Reporting procedures

Beyond legality, ethical penetration testers must operate with integrity. This includes responsible disclosure of vulnerabilities, safeguarding client data, and not exploiting findings for personal gain.

Certifications That Validate Knowledge of Core Concepts

While tools and techniques can be self-taught, certifications validate your knowledge to employers. The following are widely recognized in penetration testing:

CompTIA PenTest+: Entry-level, covering basic testing methodology and tools.
eJPT (eLearnSecurity Junior Penetration Tester): Lab-based exam ideal for beginners.
OSCP (Offensive Security Certified Professional): Industry gold standard; hands-on, 24-hour exam.
CEH (Certified Ethical Hacker): Focuses more on theory and terminology but respected in HR circles.

These certifications test your understanding of the concepts covered in this part and serve as formal proof of your readiness to move into real-world testing environments.

How to Gain Practical Experience in Penetration Testing

Practical experience is the foundation of a successful career in penetration testing. Unlike theoretical knowledge, which teaches you what vulnerabilities are, hands-on practice helps you understand how to find and exploit them in real-world environments. In this section, we explore actionable ways to gain practical experience in penetration testing, from home lab setups to participating in competitions and open-source projects.

Building Your First Home Lab

The best way to begin is by creating a virtual lab environment. A home lab allows you to practice without legal risks or damaging production systems. You don’t need expensive hardware—just a laptop or desktop with sufficient RAM and storage.

Start by installing a hypervisor such as VirtualBox or VMware Workstation. Then, set up virtual machines for both attacking and target systems. A basic setup might include:

Kali Linux: The de facto operating system for penetration testers, preloaded with hundreds of tools.
Metasploitable: A deliberately vulnerable Linux virtual machine that’s perfect for practicing exploits.
DVWA (Damn Vulnerable Web Application): A PHP/MySQL web application with known security issues.
Windows VM: To practice privilege escalation and Windows-specific attacks.

Once you have these VMs running, connect them to an internal NAT network. This isolates your testing environment from the internet while allowing communication between machines.

Your home lab can grow as you do. Add different operating systems (Linux distributions, outdated Windows versions), intentionally misconfigured services (open FTP servers, unpatched web applications), and honeypots. Use real-world scenarios, such as privilege escalation chains, weak password policies, and insecure APIs to simulate complex environments.

Capture The Flag (CTF) Competitions

Capture The Flag competitions are among the best ways to test your penetration testing skills in a safe, gamified environment. These events provide challenges in areas like reverse engineering, web exploitation, cryptography, and binary exploitation.

CTFs are hosted online regularly, and platforms like Hack The Box, TryHackMe, PicoCTF, and OverTheWire provide beginner to advanced level scenarios. These platforms offer realistic simulations that test your technical knowledge and problem-solving under pressure. Some even provide guided walkthroughs for educational purposes.

Participating in CTFs not only sharpens your skills but also builds your resume. Employers often view CTF rankings, badges, and profile completions as indicators of a candidate’s practical capability and commitment to ethical hacking.

TryHackMe and Hack The Box

Two standout platforms for hands-on learning are TryHackMe and Hack The Box. These platforms provide guided paths and challenge-based labs designed to simulate real-world security environments.

TryHackMe is especially beginner-friendly, with structured learning paths like “Pre Security,” “Complete Beginner,” and “Offensive Pentesting.” It includes interactive tutorials, notes, quizzes, and practical VMs.
Hack The Box is more advanced, with live boxes that reflect real-world misconfigurations and vulnerabilities. It’s favored by professional pentesters and often used in CTF competitions and red team training.

Both platforms allow you to build experience at your own pace, practice specific skills (web app testing, privilege escalation, networking), and join an active global community of learners and professionals.

Volunteering and Internships

One overlooked path to experience is volunteering your skills for non-profit organizations, student projects, or open-source initiatives. Many small businesses or community organizations cannot afford high-end security assessments and may welcome help from an ethical hacker under strict conditions.

Reach out to local groups, universities, or tech communities. Offer your services in exchange for documented experience. Just make sure there’s a signed agreement and a clear scope to avoid legal problems.

Additionally, look for cybersecurity internships, even unpaid ones. Internships offer exposure to professional tools and work environments. Even if you’re not doing penetration testing directly, being in a security-centric environment gives you valuable context for how security is managed at scale.

Contributing to Open Source Security Projects

Contributing to security-related open-source projects is another practical method of gaining real-world exposure. Look for GitHub repositories that deal with security tools, vulnerability scanners, exploit frameworks, or security documentation.

You might not start by writing code; you could begin with improving documentation, reporting bugs, or testing pull requests. Over time, you’ll understand how security tools are developed and maintained, and you may start contributing code or writing custom exploits.

Some high-impact open-source tools you could contribute to include:

OWASP projects (like ZAP or Juice Shop)
Metasploit Framework
Nmap scripting engine (NSE)
Nikto or sqlmap
Security automation frameworks like Ansible or Chef security modules

Every contribution you make adds to your credibility and gives you a deeper understanding of how security tools function internally.

Blogging and Documenting Your Work

Another powerful way to gain experience is to blog about your learning journey. Writing about your lab results, CTF solutions, or tool usage reinforces your knowledge and establishes you as a practitioner in the field.

Even basic topics like “How I Set Up My Pen Testing Lab,” “SQL Injection Walkthrough,” or “Privilege Escalation with WinPEAS” can get attention if well written and clear. Platforms like Medium, GitHub Pages, or your own blog are great places to publish.

Additionally, public documentation demonstrates your communication skills—something hiring managers greatly value. A well-maintained portfolio of walkthroughs and projects can help you stand out during job applications or interviews.

Getting Certified with a Hands-On Focus

Certifications aren’t always necessary, but some can offer structured, practical training environments. Certifications like the following are particularly hands-on:

eLearnSecurity Junior Penetration Tester (eJPT): A great starting point with real-world labs and no multiple-choice questions.
Offensive Security Certified Professional (OSCP): Considered the gold standard for practical penetration testing, this certification requires completing a 24-hour hands-on exam involving live exploitation.
Certified Ethical Hacker (CEH): Though more theoretical, CEH v12 includes a practical lab-based component and can serve as a stepping stone to more advanced practical certifications.

The value of certification lies not in the certificate but in the preparation process. If a certification requires you to document attacks, exploit machines, and write a report, it’s worth your time as an experience-building tool.

Joining Security Communities

Learning alone can be limiting. Join cybersecurity communities to gain feedback, mentorship, and guidance. Online forums like Reddit’s /r/netsec, Discord servers, LinkedIn groups, or local meetups can connect you with experienced professionals.

Ask questions, share what you’re working on, and seek mentorship. Many senior penetration testers are happy to offer guidance to newcomers who show initiative and curiosity.

Consider attending security conferences (even virtually), such as DEF CON, Black Hat, BSides, or Nullcon. These events often include workshops, training, and networking opportunities. You may even find scholarships or free student passes.

Practicing Report Writing

One area many beginners overlook is reporting. Being able to find a vulnerability is half the job; explaining it to non-technical stakeholders is the other half. When practicing in your lab or on platforms like TryHackMe, always write a sample report.

Include:

Executive summary
Technical details of the vulnerabilities
Steps to reproduce
Screenshots of evidence
Risk assessment (likelihood and impact)
Recommendations for remediation

Strong reporting skills can differentiate you from other candidates. It shows professionalism, attention to detail, and the ability to communicate effectively—a must in real-world engagements.

Building a Portfolio and Resume

Finally, create a portfolio showcasing your skills. It can include:

GitHub repositories of scripts or tools you’ve written
CTF writeups
Blog articles
Sample penetration testing reports
Certificates or course completions

Add these to a well-organized resume tailored to entry-level cybersecurity or penetration testing roles. Focus on practical achievements and projects rather than just listing tools you’ve used.

Building a Career in Penetration Testing

Penetration testing, often referred to as ethical hacking, is not just a job—it’s a career path that combines curiosity, persistence, technical expertise, and the drive to outsmart real-world attackers. Once you’ve acquired a solid foundation in penetration testing techniques and gained practical experience, the next step is transforming your skills into a rewarding profession. This section outlines how to launch and grow your career in penetration testing, what roles are available, and how to continue learning and evolving in this dynamic field.

Choosing Your Career Path in Penetration Testing

There are multiple pathways within penetration testing and offensive security. Depending on your interests and experience, you might specialize in any of the following areas:

Network Penetration Tester: Focuses on identifying vulnerabilities in wired and wireless network infrastructure, including routers, firewalls, and switches.
Web Application Security Tester: Specializes in testing websites and APIs for common vulnerabilities such as SQL injection, cross-site scripting (XSS), broken authentication, and insecure deserialization.
Mobile Security Tester: Analyzes the security of Android and iOS apps, identifying insecure data storage, improper cryptography usage, and flawed authentication mechanisms.
Red Team Operator: Simulates real-world attacks, often working with advanced persistence techniques, lateral movement, and social engineering to assess the resilience of an organization’s entire security posture.
Cloud Security Penetration Tester: Targets cloud infrastructure like AWS, Azure, or GCP, assessing misconfigurations, insecure APIs, privilege escalation paths, and vulnerable services in the cloud environment.
IoT/Embedded Device Tester: Deals with the testing of hardware devices like smart home appliances, wearables, and industrial control systems to uncover firmware vulnerabilities and insecure protocols.

Each of these specialties requires focused learning, tools, and hands-on practice. However, all build on a core understanding of systems, networks, scripting, and attacker methodology.

Certifications to Boost Credibility

Certifications are not always mandatory, but they do enhance credibility, especially if you’re entering the field or aiming for roles in regulated industries. Some of the most respected certifications in penetration testing include:

CompTIA PenTest+: A beginner-friendly exam that validates basic penetration testing and vulnerability management skills.
eJPT (Junior Penetration Tester): A practical certification from eLearnSecurity that assesses your ability to perform a basic pen test.
OSCP (Offensive Security Certified Professional): One of the most recognized certifications in the field. This exam involves a grueling 24-hour hands-on hacking test, requiring candidates to compromise multiple machines.
CEH (Certified Ethical Hacker): Covers theoretical and practical aspects of ethical hacking, with a broad syllabus aligned to the latest threats and tactics.
CRTP, CRTE, and similar AD-focused certifications: For testers who want to specialize in Active Directory exploitation, these hands-on labs are widely respected.

Choosing the right certification depends on your background, goals, and budget. It’s also important to remember that passing a certification is only a signal of competence—it’s your ability to apply what you know in real scenarios that truly matters.

Building a Portfolio and Resume

In penetration testing, your personal projects and experience often speak louder than your resume. A strong portfolio could include:

CTF Writeups: Capture The Flag events simulate real-world hacking scenarios. Participating in CTFs and publishing detailed writeups demonstrates your problem-solving skills and methodology.
Bug Bounty Reports: If you’ve participated in bug bounty programs, include summaries of your findings, along with impact analysis (with permission and respecting disclosure rules).
Public Tool Contributions: Contributing to open-source tools, writing plugins for frameworks like Burp Suite or Metasploit, or even creating your own scripts for automation can showcase your creativity and initiative.
Technical Blog: A well-written blog explaining your testing process, new vulnerabilities, or tool usage can build your reputation and serve as a resource for others.

When writing your resume, tailor it to reflect specific skills relevant to penetration testing, such as vulnerability assessment, scripting, familiarity with testing tools, knowledge of attack vectors, and reporting. Keep it factual and results-oriented—mention what you did, how you did it, and what the impact was.

Getting That First Job

Landing your first job in penetration testing can be challenging, especially with limited professional experience. Here are some ways to increase your chances:

Internships and Apprenticeships: These provide valuable hands-on experience and a foot in the door. Many companies now offer structured security internships, including opportunities in offensive roles.
Start with SOC or Blue Team Roles: Gaining experience in Security Operations Centers (SOC), incident response, or threat hunting roles helps you understand attacker behavior, which later makes you a better offensive security professional.
Freelancing or Contract Work: Platforms like HackerOne, Bugcrowd, and Synack offer bounty programs and private engagements that let you earn real-world experience and compensation.
Small Consulting Firms and MSPs: They may be more open to hiring entry-level testers and often expose you to a variety of environments and clients, speeding up your learning curve.
Community Engagement: Attend local or virtual security meetups, join Discord and Slack groups, participate in forums like Reddit’s /r/netsec or Stack Exchange, and follow industry experts on social media. Often, job opportunities come through networking and referrals.

Advancing Your Career

Once you’ve secured an entry-level role and gained a few years of experience, you can begin thinking about how to grow. Key options include:

Specializing Further: Becoming a subject matter expert in cloud security, web apps, or Active Directory can make you more valuable and open doors to higher-paying roles.
Moving into Red Teaming: Red teaming focuses more on stealth and long-term operations rather than vulnerability scanning and exploits. It’s ideal for testers who enjoy strategic thinking and advanced adversary simulation.
Becoming a Security Consultant: This involves working directly with clients, often in highly regulated industries. You’ll need strong communication skills and the ability to translate technical findings into business terms.
Transitioning into Security Research: If you love discovering new vulnerabilities or creating exploit code, a role in vulnerability research might be a good fit. This often requires programming skills and a deep understanding of system internals.
Leadership Roles: Senior testers can grow into positions like Penetration Testing Team Lead, Security Assessment Manager, or even Chief Information Security Officer (CISO), depending on their leadership and business acumen.

Your long-term career path can be technical, managerial, or a blend of both. What matters is continual learning and adaptability.

Staying Current in a Fast-Changing Field

Cybersecurity evolves rapidly. New vulnerabilities, techniques, and defenses emerge weekly. To stay ahead, penetration testers must commit to lifelong learning. Some strategies include:

Follow Vulnerability Feeds and Blogs: Resources like CVE databases, Hacker News, Rapid7, and security researcher blogs can keep you informed about emerging threats.
Read Security Books and Whitepapers: Books like “The Web Application Hacker’s Handbook,” “Red Team Field Manual,” and “The Hacker Playbook” remain timeless resources.
Watch Conference Talks: Events like DEF CON, Black Hat, and OWASP AppSec feature presentations from top researchers. Most are available on YouTube for free.
Experiment in Labs and Home Labs: Platforms like Hack The Box, TryHackMe, Offensive Security’s Proving Grounds, and building your own test lab at home allow for safe, legal practice.
Contribute to the Community: Sharing knowledge, reporting bugs, or helping new learners fosters professional relationships and can raise your profile in the industry.

Final Thoughts

A career in penetration testing offers a mix of intellectual challenge, technical problem-solving, and tangible impact. You get to think like an attacker, uncover flaws before real criminals do, and help organizations stay safe in a digital world. However, success doesn’t happen overnight. It requires curiosity, constant learning, and a willingness to step outside your comfort zone.

Whether you’re just starting or already gaining experience, remember that the cybersecurity industry values passion and persistence. Keep practicing, build your network, stay ethical, and never stop learning. With dedication, penetration testing can become not just your career—but your craft.