7 Penetration Testing Best Practices With Examples in 2024

Penetration testing has emerged as a critical resource for companies aiming to bolster their cybersecurity measures. The figure above supports the claim that it is gaining relevance. Penetration testing is the practice of executing simulated cyber attacks on computer systems, networks, or web applications to uncover and remedy security weak points. This article explores the most effective methods of penetration testing, illustrating each with specific examples.

1. Planning and Scope Definition

Planning and scope definition are essential in penetration testing to ensure effectiveness and alignment with an organization’s specific needs. Planning sets the roadmap for methodologies and tools to be used, optimizing resource management. 

Scope definition outlines the boundaries of the test, identifying which data and systems are included, thereby ensuring legal compliance and focusing efforts on critical assets. Together, these practices help conduct a targeted and responsible test, prevent unauthorized access, and minimize disruption to normal business operations.

Example: After the infamous PlayStation Network breach, Sony reportedly revamped its approach to cybersecurity, including the planning and scoping phases of their penetration testing.¹ They focused on segmenting the testing processes to cover various parts of their network and digital assets more effectively, ensuring that critical vulnerabilities could be identified and addressed in a systematic manner.

2. Utilize Multiple Tools and Techniques

Utilizing multiple tools and techniques in penetration testing is crucial for ensuring comprehensive security assessments. Different penetration tools and methods are designed to uncover various types of vulnerabilities, and relying solely on one may leave security gaps. A mix of automated and manual techniques ensures both breadth and depth in testing, capturing both common and complex vulnerabilities. 

This approach also offers redundancy, validating the reliability of findings across different tools. Additionally, the ever-evolving nature of cybersecurity threats demands adaptability in testing methods to effectively counter new vulnerabilities. Therefore, using a diverse set of tools and techniques not only enhances the thoroughness of the test but also strengthens the organization’s overall security posture.

Example: Suppose a security team is tasked with conducting a penetration test on a web application to identify potential vulnerabilities:

Automated Scanning: The team starts with automated scanning tools like OWASP ZAP or Invicti to quickly identify common vulnerabilities such as SQL injection, XSS (Cross-Site Scripting), and CSRF (Cross-Site Request Forgery). These tools can scan the entire application and provide an initial list of potential security issues.

Manual Testing and Exploitation: After the automated scan, the team performs manual testing to explore deeper into the application logic and session management flaws that automated tools might miss. For example, they manually test for business logic errors that could be exploited to bypass authentication or authorization controls.

Source Code Analysis: The team also uses static application security testing (SAST) tools to analyze the source code of the application. Tools like SonarQube or Checkmarx can identify vulnerabilities such as insecure coding practices and hard-coded secrets, which are not always apparent through black-box testing methods.

Dynamic Analysis: Concurrently, dynamic application security testing (DAST) tools are applied to execute the application and monitor its behavior in real time. This helps in identifying runtime issues such as memory leaks or input validation errors.

3. Legal Clearance

Legal clearance is important for penetration testing because it ensures that testing activities are authorized and comply with relevant laws and regulations. This clearance protects both the organization conducting the test and the penetration testers from legal repercussions that could arise from unauthorized access to systems, networks, or data. It formalizes the consent to probe and potentially exploit vulnerabilities, which might otherwise be considered illegal activities under laws such as the Computer Fraud and Abuse Act in the United States.

Additionally, legal clearance helps define the boundaries and scope of the testing, ensuring that all parties understand the limits and objectives of the engagement. This is crucial for maintaining trust and protecting both the testers and the client from potential legal and reputational harm.

Example: When conducting penetration tests, companies like IBM or Google ensure that they have comprehensive legal agreements in place that specify the scope of the test, the methodologies to be used, and the systems that can be tested. ² These agreements are crucial in ensuring that the tests do not overstep legal boundaries and that all parties involved understand and consent to the potential impacts and procedures of the testing.

4. Use a Methodical Approach

Using a methodical approach in penetration testing is critical because it ensures thoroughness, consistency, and reliability in identifying vulnerabilities within an IT infrastructure. A structured methodology, such as the Penetration Testing Execution Standard (PTES), guides testers through a series of clearly defined phases. These phases typically include planning, reconnaissance, vulnerability assessment, exploitation, post-exploitation, and reporting.

Example: Google is known for its rigorous security practices, which include methodical penetration testing as part of its security assessment procedures. Google uses both the Penetration Testing Execution Standard (PTES) and its own internal methodologies to conduct thorough and effective penetration tests. ³ This structured approach helps in systematically identifying vulnerabilities across its vast network and software systems.

The following are penetration testing methodologies:

• OWASP Testing Guide: The Open Web Application Security Project (OWASP) provides a comprehensive methodology for testing web applications. It covers areas such as authentication, session management, input validation, and server configuration vulnerabilities.
• PTES (Penetration Testing Execution Standard): This standard is designed to provide a common language and scope for performing penetration testing. PTES covers everything from pre-engagement interactions and intelligence gathering to vulnerability analysis, exploitation, post-exploitation, and reporting.
• OSSTMM (Open Source Security Testing Methodology Manual): Developed by the Institute for Security and Open Methodologies (ISECOM), the OSSTMM focuses on the security testing of networks, systems, and applications. It provides a scientific approach to testing, measuring, and reporting on operational security.
• NIST SP 800-115: This guide from the National Institute of Standards and Technology (NIST) provides technical guidelines for penetration testing organizations. It outlines planning, conducting, and analyzing penetration tests.
• ISSAF (Information Systems Security Assessment Framework): Developed by the Open Information Systems Security Group, this framework offers detailed procedures and techniques for securing IT systems and networks. It includes vulnerability assessments and penetration testing components.
• EC-Council’s Licensed Penetration Tester (LPT) Methodology: This methodology emphasizes a repeatable and measurable approach to penetration testing and is part of the EC-Council’s certification process.
• PCI DSS Penetration Testing: This methodology is specific to organizations handling credit card data and is part of the Payment Card Industry Data Security Standard (PCI DSS). It includes requirements for regular testing to protect cardholder data environments.

5. Testing from Different Perspectives

This practice helps identify vulnerabilities that might be exploited by various types of attackers, whether they are external threats, internal employees, or even third-party vendors with limited access. By simulating attacks from these diverse viewpoints, organizations can better understand potential security weaknesses from all angles and implement more effective defenses. This comprehensive approach ensures that security measures are robust against a wide array of attack vectors, reducing the risk of overlooked vulnerabilities that could be critical.

Example: The tester performs authentication bypass attempts both as an unauthenticated user trying to access restricted areas and as a logged-in user attempting to escalate privileges. This dual perspective helps identify security lapses within both external and internal threat models.

6. Maintain a Controlled Environment

Maintaining a controlled environment during penetration testing is a best practice because it ensures the test does not impact the actual operational environment or real data. This controlled setting allows testers to simulate attacks and identify vulnerabilities without the risk of causing system downtime, data breaches, or other disruptions to daily business operations. 

Additionally, it helps in accurately assessing the security landscape by isolating variables and ensuring the stability and consistency of the test results. This controlled approach also facilitates a safer environment to test more aggressive security breaches without the fear of real-world repercussions.

Example: Penetration tests are conducted on a mirrored production environment, which is isolated from the actual production network to avoid service disruptions or data breaches during testing.

7. Document Everything

Documenting everything during penetration testing is a best practice because it ensures accountability, facilitates compliance with legal and regulatory requirements, supports effective remediation, enhances knowledge sharing for continuous improvement, and provides a historical record for future reference. This comprehensive documentation aids in tracking changes over time, verifying the security measures implemented, and maintaining an organized approach to cybersecurity.

Example: Detailed logs of each test case are maintained:

• Timestamps of when each test was performed
• Techniques and tools used
• Results and screenshots as evidence This documentation will be crucial for verifying the tests performed and for future reference.

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External Links

• 1. “Sony PlayStation suffers massive data breach” Reuters.
• 2. “Penetration Testing Guidelines“Google
• 3. “Penetration Testing Guidelines“Google