10 Penetration tester Interview Questions and Answers for security engineers

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1. What inspired you to become a penetration tester, and how did you get into this field?

As a teenager, I became interested in hacking and cybersecurity thanks to movies and books that romanticized these topics. However, it wasn't until I actually started playing around with systems that I realized just how much I enjoyed the process of trying to bypass security measures and find vulnerabilities.

  1. To pursue my interest further, I studied computer science in college and started taking online courses on cybersecurity.
  2. I also took part in various capture the flag competitions and challenges to test and improve my skills in penetration testing.
  3. Eventually, I got a job at a security firm as a junior penetration tester and worked my way up the ladder over the years.

In terms of concrete results, I've helped secure client networks by identifying critical vulnerabilities that could have potentially led to data breaches. For example, in my previous role, I helped one of our clients by identifying a vulnerability that allowed unauthorized access to their database, which posed a significant risk to their sensitive data. By exploiting and demonstrating the flaw to the client, we were able to recommend and implement a solution to mitigate the risk and secure their network.

2. What kinds of tools and technologies do you use as a penetration tester, and how do you stay up-to-date on new developments?

As a penetration tester, I use a variety of tools and technologies to identify and exploit vulnerabilities in target systems. Some of the commonly used tools I use include:

  1. Nmap: a network scanner which helps in identifying open ports and identifying vulnerabilities.
  2. Metasploit: a software which helps in creating payloads to exploit vulnerabilities, in various operating systems and applications.
  3. Wireshark: a traffic analysis tool which helps in identifying network traffic and packet analysis.
  4. Burp Suite: a powerful tool used for web application security testing and analysis.
  5. Kali Linux: a popular operating system used by penetration testers as it includes a wide range of tools used for penetration testing.

In order to keep up-to-date with new developments in the field, I constantly read industry news and updates. I also attend conferences, participate in online forums and discussion boards, and maintain a network of contacts in the industry. For instance, I recently attended a cybersecurity conference where I learned about a new technique using machine learning to detect and prevent cyberattacks. After researching and implementing this technique, we were able to reduce the attack surface by 20% on one project.

3. How do you approach the process of assessing a client's security posture, and what kinds of tests do you recommend for different types of organizations?

When assessing a client's security posture, my first step is always to gather as much information as possible about their current systems, processes, and vulnerabilities. I'll start with a comprehensive interview process to understand their current security measures and any past security incidents they may have experienced.

  • I'll then conduct a vulnerability assessment to prioritize any immediate security concerns. This might include penetration testing, scanning their network and applications, and reviewing their security configurations.
  • For smaller organizations or those just starting with cybersecurity measures, I will recommend a security baseline assessment to provide them with a snapshot of their current security posture.
  • For larger organizations, I will recommend a continuous security assessment, which is an ongoing process of evaluating and remediating threats.

Based on my findings, I will work with the client to create a tailored security plan that meets their specific needs and aligns with their business goals. I often recommend a combination of technical and non-technical measures, such as:

  1. Implementing multi-factor authentication to reduce the risk of password compromises.
  2. Using encryption to protect sensitive data both in transit and at rest.
  3. Developing an incident response plan to prepare for potential breaches.
  4. Conducting regular security awareness training to educate employees on how to prevent and detect security risks.

Recently, I worked with a financial services company to improve their security posture. After an initial assessment, I found several vulnerabilities in their web application, including SQL injection and XSS. I recommended implementing a web application firewall and enhancing their input validation process. As a result, they were able to prevent further vulnerabilities and protect sensitive customer data.

4. How do you ensure that your tests are ethical and legally compliant, and what kinds of safeguards do you have in place to protect sensitive data?

As a penetration tester, I believe that ensuring the ethical and legal compliance of our tests is of utmost importance. This is why I adhere to strict guidelines established by international security standards such as ISO/IEC 17025 and follow ethical hacking codes of conduct like EC-Council’s Code of Ethics.

During our tests, sensitive data is handled with extreme caution. We've put in place strong safeguards such as access controls for the data, two-factor authentication for sensitive systems, and technical measures such as encryption and decryption of data. We also use secure and encrypted communication protocols that are audited daily to ensure their integrity.

At the end of our testing process, we provide a comprehensive report that contains in-depth analyses of our findings with solutions that our clients can use to improve their security posture. We ensure that all our tests and reports are cleared and approved by our clients before making them public.

Last year, one of our clients came to us with a security vulnerability that would have exposed sensitive customer data. Through our testing, we were able to identify the vulnerability and provide a practical solution. Our client was able to mitigate the risk, prevent data leaks, and avoid any significant financial and reputational damage by implementing our recommended solution.

  1. Adhere to ethical hacking codes of conduct (e.g., EC-Council's Code of Ethics).
  2. Follow international security standards (e.g., ISO/IEC 17025).
  3. Use strong safeguards and encryption protocols for sensitive data.
  4. Provide a comprehensive report that is cleared and approved by clients before being made public.
  5. Achieve practical results such as identifying and resolving vulnerabilities to prevent data leaks and financial/reputational damage.

5. What are some of the most common vulnerabilities you've discovered in your work as a penetration tester, and how do you recommend organizations guard against them?


  1. SQL Injection:

    • As a penetration tester, I have discovered that SQL injection is one of the most common vulnerabilities in many web applications.
    • Organizations can guard against it by using prepared statements, input validation, and stored procedures.
    • For example, in one of my recent projects, I identified an SQL injection vulnerability in a web application that allowed an attacker to access the sensitive information of customers. As a result, I recommended the organization to implement parameterized queries and input validation, which helped them mitigate the vulnerability.
  2. Cross-site scripting (XSS):

    • XSS is another common vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users.
    • Organizations can prevent this vulnerability by implementing proper input validation and output encoding.
    • In a project I worked on last year, I identified an XSS vulnerability in a web application that allowed an attacker to steal user cookies and perform unauthorized actions on behalf of legitimate users. I recommended the organization to implement output encoding and properly sanitize user input, which helped them close the vulnerability successfully.
  3. Privilege escalation:

    • This vulnerability allows an attacker to gain access to sensitive data or functions by elevating their privileges or bypassing access control mechanisms.
    • Organizations can guard against this vulnerability by implementing proper access controls and privilege separation.
    • Recently, I identified a privilege escalation vulnerability in a client's server software that allowed an attacker to access the root account and take complete control of the system. I recommended the organization to implement least privilege access control and role-based access control, which helped the organization mitigate the vulnerability.

In conclusion, by being aware of common vulnerabilities such as SQL injection, XSS, and privilege escalation, organizations can take proactive measures to prevent these vulnerabilities from being exploited. Proper input validation, output encoding, access controls, and privilege separation are some of the best practices that organizations should implement to safeguard their systems and data against threats.

6. How do you communicate your findings to clients, and what kinds of reports or other deliverables do you produce?

As a penetration tester, I realize that accurate and thorough reporting is an essential part of the job. In communicating my findings to clients, I prioritize delivering clear and concise reports that are easy for non-technical personnel to understand.

  1. First, I begin by outlining the scope and methodology of the test, making sure the client understands the objectives of the engagement.
  2. Second, I present my findings and explain the impact of each vulnerability. I use clear and simple language, avoiding technical jargon wherever possible, to ensure that my report is understandable to all stakeholders.
  3. Third, I offer concrete examples and evidence to illustrate my findings. For instance, I may include screenshots, logs or command outputs to back up my claims. This level of detail helps clients understand the severity of each vulnerability.
  4. Finally, I offer actionable recommendations, outlining steps the client can take to remediate the vulnerabilities I've uncovered. I work with clients to prioritize these recommendations based on the risks posed by each vulnerability.

Overall, I believe that strong communication and reporting skills are just as important as technical expertise. In my previous role, I was able to help a client reduce their risk of a data breach by 85% after a comprehensive penetration test. My detailed report helped them identify critical vulnerabilities and address them before they could be exploited.

7. What kinds of challenges have you faced in your work as a penetration tester, and how have you overcome them?

As a penetration tester, I have faced several challenges in my work, most notably when performing vulnerability assessments of complex software systems. In one instance, I was tasked with assessing the security of a large software application developed by a financial institution. The application had a very complex architecture and comprised of several sub-systems.

During the assessment, I discovered several vulnerabilities, but the most critical one was related to an encryption mechanism that the application used to secure sensitive data. I found that the encryption mechanism had a serious flaw that could allow an attacker to decrypt the data without the key. Fixing the encryption flaw would require a significant overhaul of the application's codebase, which would take several months and cost the company a lot of money.

To overcome this challenge, I worked closely with the company's developers to find a way to fix the encryption flaw without completely overhauling the codebase. Together, we developed a patch that fixed the flaw and maintained the application's functionality. After the patch was deployed, I conducted additional penetration testing to verify that the fix was effective, and no new vulnerabilities were introduced.

Another challenge I faced during a penetration testing engagement was when I was hired to assess a company's network security. I was only given limited access to the network, which made it challenging to conduct a comprehensive assessment. However, I was able to overcome this challenge by using various techniques, such as social engineering, to gain access to the network. Once I gained access, I was able to conduct a thorough assessment and identify several critical vulnerabilities.

  1. To fix the vulnerabilities, I worked closely with the company's IT department to create an action plan that detailed the steps required to mitigate each issue.
  2. We prioritized the vulnerabilities based on their criticality and started fixing them one by one.
  3. After a few weeks, we were able to fix all the critical vulnerabilities, and I conducted additional testing to verify that no new issues were introduced.

Overall, I learned that communication and collaboration are essential when dealing with complex security issues. Working closely with the client's development and IT teams helped me overcome some of the significant challenges I faced as a penetration tester.

8. What sets you apart from other penetration testers, and what qualities do you think are most important for success in this field?

As a penetration tester, I believe that my unique blend of technical abilities, creativity, and strong communication skills set me apart from others in the field. I approach every project with a hacker mindset and enjoy discovering new vulnerabilities and potential exploits.

  1. First and foremost, I have a deep understanding of both offensive and defensive security techniques. I am fluent in multiple programming languages and have experience with a variety of operating systems and network protocols. This allows me to think outside the box when attempting to breach an organization's defenses, and also helps me to identify and remediate vulnerabilities effectively.
  2. Secondly, I am a meticulous researcher. Before diving into a project, I conduct thorough reconnaissance to collect as much information as possible about the target organization. This helps me to identify areas of weakness and tailor my attack plan specifically to their environment.
  3. Thirdly, I am a creative problem solver. I frequently think outside of the box when faced with challenging issues or roadblocks, and come up with innovative solutions to problems. This has enabled me to discover vulnerabilities that others have overlooked.
  4. Finally, I possess excellent communication skills. I understand that my findings are only as effective as my ability to clearly communicate them to stakeholders. Whether presenting to technical staff or senior management, I am able to effectively convey complex concepts in a concise and understandable way.

To achieve success in this field, I believe that a combination of technical skills, creativity, and strong communication abilities are essential. Additionally, remaining up-to-date on the latest attack methodologies, security trends, and emerging technologies is crucial to staying ahead of the curve.

9. How do you maintain the trust and confidence of your clients, and what kinds of relationships do you build with them?

At the core of my work as a penetration tester is building and maintaining positive client relationships. Communication is key to ensuring that my clients are well-informed and comfortable with the security assessments I perform.

I always make sure to keep my clients informed. Regular communication, updates, and comprehensive reports are key to maintaining trust with my clients. I understand that transparency is essential in this business and that clients require the utmost professionalism and honesty from me.

One of the tactics that I have used in the past is to provide clients with detailed reports of my findings, with recommendations and best practices to improve their security measures. By providing these reports, I have been able to build trust and demonstrate my knowledge to my clients. Additionally, I have offered clients training sessions on cybersecurity basics to help them make informed decisions when it comes to improving their security.

One example of how my approach has improved relationships with clients is with a large retail company that I worked with. They initially hired me to perform a single penetration test. After seeing the quality of my work and the value that I brought, they continued to engage me for multiple projects. They cited my ability to communicate transparently and my in-depth knowledge and expertise as the reasons why they chose to continue working with me.

  1. Keeping lines of communication open and being transparent
  2. Providing detailed reports
  3. Offering training sessions on cybersecurity topics

By using these tactics and strategies, I have been able to build and maintain strong relationships with my clients, ensuring that they trust in my ability to help them identify and mitigate security risks.

10. What advice would you give to someone who is interested in pursuing a career as a penetration tester, and how can they best prepare for this role?

For anyone interested in pursuing a career as a penetration tester, my advice would be to start by obtaining relevant certifications such as Certified Ethical Hacker (CEH) and Offensive Security Certified Professional (OSCP). These certifications demonstrate a strong foundation of knowledge in penetration testing methodologies and tools.

Furthermore, building hands-on experience and knowledge is important in this field. Playing with vulnerable applications in your personal lab or participating in bug bounty programs can help develop practical skills. Additionally, joining local security meetups or participating in online security communities is a great way to learn from others, and develop a valuable network.

It's also important to stay up-to-date with the latest security vulnerabilities and trends in the industry. Keeping up with research papers, attending industry conferences, and following security bloggers can help maintain your knowledge base and keep your skills sharp.

Finally, having good communication skills and being able to work in a team is critical for success as a penetration tester. The ability to explain technical concepts to non-technical audiences and work collaboratively with other professionals will help build a strong reputation and lead to new opportunities.

  1. Obtain relevant certifications (e.g., CEH, OSCP)
  2. Build practical experience and knowledge
  3. Participate in security communities and network with peers
  4. Stay up-to-date with industry trends and vulnerabilities
  5. Develop strong communication and team skills


Congratulations on finishing this list of 10 Penetration tester interview questions and answers for 2023! Now that you have valuable insights into what interviewers might ask, it's time to prepare for your job hunt. One of the first steps is to write a killer cover letter. Check out our guide on writing a standout cover letter. Next, make sure to prepare an impressive CV that highlights your experience and skills as a security engineer. Our guide on writing a winning resume for security engineers can help you with that. Finally, if you are looking for remote security engineer jobs, look no further than our job board at Remote Rocketship. Good luck with your job search!

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