Preparing for a Junior Penetration Tester Interview

Discover our expert tips and advice for preparing for a Junior Penetration Tester interview!

Preparing for a Junior Penetration Tester Interview

Penetration Testing is an area where demand from employers is at its highest, with a wealth of learning capabilities and a highly competitive salary for candidates.

We previously looked at how to become a Penetration Tester. In this guide, we’re diving into the tips and advice from our inside experts, and answering those all-important pentester interview questions, most specifically, for a Junior Penetration Tester.

Do your research

Carrying out research on the company and the role you have applied for, as preparation is vital in making a positive first impression!

Take a look at the company website and read through a handful of their blog articles and guides to learn as much as you can. It’s great to mention recent awards, company developments, or appearances in the media to show that you have taken the time to carry out research.

Meanwhile, a great way to better understand the company is by checking out review websites, including TrustPilot, Feefo, and, as well as any of the company’s social media accounts.

Glassdoor provides an overview of interview experiences from other candidates, giving you an idea of the types of Penetration Testing job interview questions you’ll be asked.

Keep up with the industry

In the world of offensive security, keeping up with the rapidly evolving industry is vital, and an interviewer will want to know that you are doing everything possible to keep updated.

There are some fantastic influencers in the world of offensive security that regularly share insights. We recommend keeping up with John Hammond, Tyler Ramsbey, Alh4zr3d, InfoSec Pat, and InsiderPHD.

Other mediums include Bleeping Computer, Krebs On Security, Symantec Enterprise, Malwarebytes, and CyberScoop.

Attending conferences, podcasts, webinars, and industry events is also a fantastic way to keep up with the rapidly evolving industry. Some fantastic events include Black Hat, DEFCON, Security BSides, while our industry experts also recommend The Shared Security and Security Now! podcasts.

Ongoing learning and development

With learning paths dedicated to penetration testing and ethical hacking, we recommend completing our Jr Penetration Tester Learning Path, which explores the fundamental pentesting methodologies to become a Junior Penetration Tester. The learning path introduces you to web application hacking and privilege escalation, equipping you with the practical skills to perform security assessments against web applications and enterprise infrastructure.

To expand your knowledge, we also recommend that you complete:

CompTIA Pentest+ Learning Path (Easy)

Gain hands-on exercises and practical exam preparation to prepare you for the CompTIA PenTest+ exam. We’ll even give you an exclusive 10% discount on the exam after completing the learning path!

Offensive Pentesting Learning Path (Intermediate)

Prepare for real-world penetration testing as you master the industry-standard tools to find vulnerabilities in machines in realistic attack scenarios.

Red Teaming Learning Path (Intermediate)

Level up with more advanced topics and understand how to execute adversary attack emulations as a Red Team Operator.

Getting to know you

Some critical skills required of Penetration Testers are communication, problem solving, adaptability, and the eagerness to learn. The interviewer will ask you some personal questions to get to know you better and understand how you will fit into the company.

They will want to know why you want to become a Junior Penetration Tester and understand your work ethic, goals, skillset, strengths and weaknesses, and whether you’ll be a great cultural fit for the team.

Some examples of Junior Penetration Tester interview questions include:

  • Why do you want to be a Junior Penetration Tester?
  • Where do you see yourself in five or ten years?
  • Why should we hire you?
  • Are you comfortable with coding and scripting?
  • How would your coworkers or your supervisor describe your work ethic?
  • What is your greatest strength and weakness?
  • Why do you want to work for us?

Preparing for technical questions

To ensure you’re up to speed with the technical requirements of a Penetration Tester, you’ll be asked a series of technical questions. Be sure you brush up on your core technical skills with Network Fundamentals, Windows Fundamentals, Linux Fundamentals, and our How the Web Works modules.

Common Penetration Testing interview questions and answers include:

Can you explain penetration testing, and why it is important?

Penetration testing is an ethically-driven attempt to test and analyse the security defences to proactively search for vulnerabilities in the network infrastructure and web applications. A penetration test involves using the same tools, techniques, and methodologies that someone with malicious intent would use in real-world attacks. Penetration tests are important as they serve as a way to examine whether an organisation's security policies are genuinely effective.

What are the different penetration phases?

The five phases in pentesting are reconnaissance, enumeration, exploitation, privilege escalation, and post-exploitation.

  1. Reconnaissance - Pose as the hacker to gain information about a company, including details of the network topology, operating systems and applications, user accounts, etc.
  2. Enumeration / Scanning - Identify the potential ways to hack into a company using various tools to identify open ports. For example, finding a web server that may be potentially vulnerable.
  3. Exploitation - Leveraging vulnerabilities discovered on a system or application. This stage can involve the use of public exploits or exploiting application logic.
  4. Privilege Escalation - Once you have successfully exploited a system or application (known as a foothold), you would then attempt to expand your access to a system.
  5. Post-Exploitation - This stage involves gathering any final information as a privileged user, and covering your tracks by removing logs and any evidence that the system was accessed. You would also conduct a report to detail your findings.

What is an SQL injection?

As one of the most common web hacking techniques, SQL injection is a code injection technique used to attack data-driven applications. It allows attackers to interfere with the queries that an application makes to its database.

What is an open redirect?

Open redirect is a vulnerability that allows a user to control a redirect or forward to another URL, which is very common in phishing attacks.

Explain the difference between a penetration test and a vulnerability test.

Penetration testing aims to exploit a security gap, while vulnerability testing checks for known exposures in firewalls, routers, switches, servers and applications. Both are equally important and should regularly be part of an organisation’s security practice.

Explain the difference between a black, white, and grey box test.

In black box testing, the internal working structure of the application is unknown, whereas in white box testing, the internal working structure is known. Grey box testing combines the two, whereby the tester partially understands the application's internal working structure.

How do you keep updated with offensive security news?

Staying up-to-date with the latest in offensive security is crucial as a Penetration Tester. Reading news articles and following offensive security professionals on social media is highly beneficial.

Meanwhile, attending conferences, podcasts, webinars, and industry events is also a fantastic way to keep up with the rapidly evolving industry.

Preparing for scenarios

You will likely be asked a series of scenario-based questions to understand your critical thinking mindset and how you might react during certain work-related scenarios. The interviewer wants to understand how you would respond to threats and why you would take your chosen approach.

Top tip! Learning through real-world scenarios can help set the foundations for approaching a realistic pentesting environment. Our Jr Penetration Tester Learning Path explores the fundamental pentesting methodologies and common scenarios of a Junior Penetration Tester, helping you to prepare for the scenario-based questions you may be asked.

For example, you may be asked:

What measures would you put in place to prevent brute forcing?

Brute forcing can be prevented with account lockout mechanisms, CAPTCHA, IP-based restrictions, and multi-factor authentication.

How would you remotely access a service that can only be accessed from within an internal network?

Set up a VPN server that is accessible from the public network. A common method of an attacker gaining access to a local service is to find a way to gain control over a local machine and use that to access other local services/machines.

How would you allow regular users to run bash scripts as root, and which way is most secure?

​​Granting regular users to execute scripts as root always carries risks, as a minor lapse in configuration can be misused or create vulnerabilities to help an adversary elevate their privileges. However, sudo is generally the most secure way to achieve this on Unix-like systems.

To make this as secure as possible, you can limit the scope of sudo, secure the script, monitor usage, and educate users about the risks and responsibilities of sudo access. They should understand what the scripts do and know the potential dangers of running commands as root.

While there is no perfectly secure solution, these steps can help reduce the risk. Ultimately, the best security practice is to avoid running scripts as root wherever possible.

If you could obtain an NTLM hash but could not decrypt it, how would you use this knowledge to obtain access to the target host?

The NTLM hash itself can be used to authenticate in what's known as a Pass-The-Hash attack, meaning you do not need to know the plaintext password. Pass-The-Hash can be executed with Mimikatz and similar tools, allowing you to authenticate to the target host as the user the hash corresponds to as if you knew the password.

Good luck!

We hope the top tips from our pentesting experts help you feel more confident and prepared for your Junior Pentesting interview!

Don’t panic if you don’t know the answer to a question. Think outside the box and explain your own solution to show you have the ideal mindset and initiative. The interviewer will understand that much of the learning will take place on the job, so try to answer as best as you can.

Don’t forget to brush up on your skills with our Jr Penetration Tester Learning Path, which explores the fundamental pentesting methodologies to become a Junior Penetration Tester, covering a wide array of tools and real-life analysis scenarios relevant to a Junior Penetration Tester position.