Principal Penetration Tester

Methodfi; Belfast; On-site; GBP 80,000 - 100,000; Full time

Job summary

A leading technology company is seeking a highly skilled Principal Penetration Tester with CHECK Team Lead (CTL) status to lead complex testing engagements across various platforms for a diverse client base. This senior role involves mentoring junior testers, automating processes, and producing actionable reports. The ideal candidate will have at least 5 years of experience, expertise in cloud security, and proficiency in key penetration testing tools. The role is based in Belfast, UK, with competitive benefits that support your growth and well-being.

Benefits

Discretionary annual performance bonus

Flexible working arrangements

Highly competitive pension scheme

Private healthcare

Employee Assistance Programme

35 days holiday

Learning and development investment

Opportunities to volunteer and give back

Qualifications

• CHECK Team Lead (CTL) status - Infrastructure preferred; Applications also considered.
• Current UK SC Clearance.
• Minimum 5 years’ penetration testing experience, with a proven track record of complex engagements.
• Proven experience in cloud security reviews (AWS, Azure, GCP).
• Deep expertise in web, mobile, and network penetration testing methodologies.
• Advanced knowledge of operating systems (Linux, Windows, Active Directory).
• Familiarity with cloud environments and ability to perform cloud security reviews.
• Proficiency with tools such as BurpSuite Pro, Nmap, Nessus, Metasploit, and Kali Linux.
• Strong scripting skills (Python, Shell, etc.).
• Excellent communication and technical report writing skills.

Responsibilities

• Lead and execute penetration tests across infrastructure, cloud, web, and mobile applications.
• Manage end‑to‑end engagements: from scoping and kick‑off sessions to delivery and client debriefs.
• Produce detailed, actionable reports outlining vulnerabilities and tailored remediation steps.
• Stay ahead of emerging threats by researching new offensive techniques and integrating them into our methodology.
• Automate repetitive tasks and streamline testing processes through scripting.
• Mentor and coach junior testers, supporting their technical growth and career development.
• Enhance tools and methodologies, ensuring our services remain cutting‑edge.
• Support pre‑sales efforts as a subject-matter expert in penetration testing.
• Communicate findings effectively to both technical and non‑technical stakeholders.
• Contribute to thought leadership through blogs, white papers, or speaking engagements.

Skills

CHECK Team Lead (CTL) status

Penetration testing experience

Cloud security reviews

Web and mobile penetration testing

Operating systems knowledge

Proficiency with penetration testing tools

Strong scripting skills

Communication skills

Tools

BurpSuite Pro

Nmap

Nessus

Metasploit

Kali Linux

Job description

We’re looking for a highly skilled Principal Penetration Tester with CHECK Team Lead (CTL) status to join our dynamic security team. This is a senior, hands‑on role where you’ll lead and deliver complex penetration testing engagements across infrastructure, cloud, web, and mobile applications for a diverse range of clients, including software, fintech, manufacturing, engineering, legal, and public sector organisations.

You’ll play a pivotal role in shaping our offensive security services—coordinating end‑to‑end testing, mentoring junior testers, and contributing to the evolution of our methodologies. If you thrive on tackling challenging security problems, enjoy working in a collaborative environment, and want to keep pushing your technical boundaries, we’d love to hear from you.

What You’ll Do

• Lead and execute penetration tests across infrastructure, cloud, web, and mobile applications.

• Manage end‑to‑end engagements: from scoping and kick‑off sessions to delivery and client debriefs.

• Produce detailed, actionable reports outlining vulnerabilities and tailored remediation steps.

• Stay ahead of emerging threats by researching new offensive techniques and integrating them into our methodology.

• Automate repetitive tasks and streamline testing processes through scripting.

• Mentor and coach junior testers, supporting their technical growth and career development.

• Enhance tools and methodologies, ensuring our services remain cutting‑edge.

• Support pre‑sales efforts as a subject‑matter expert in penetration testing.

• Communicate findings effectively to both technical and non‑technical stakeholders.

• Contribute to thought leadership through blogs, white papers, or speaking engagements.

Essential Skills

• CHECK Team Lead (CTL) status - Infrastructure preferred; Applications also considered.

• Current UK SC Clearance.

• Minimum 5 years’ penetration testing experience, with a proven track record of complex engagements.

• Proven experience in cloud security reviews (AWS, Azure, GCP).

• Deep expertise in web, mobile, and network penetration testing methodologies.

• Advanced knowledge of operating systems (Linux, Windows, Active Directory).

• Familiarity with cloud environments and ability to perform cloud security reviews.

• Proficiency with tools such as BurpSuite Pro, Nmap, Nessus, Metasploit, and Kali Linux.

• Strong scripting skills (Python, Shell, etc.).

• Excellent communication and technical report writing skills.

Nice‑to‑Have

• Additional certifications: OSCP, CSTL/CCT, Cyber Scheme, CREST.

• UK Cyber Security Council Chartership (Principal or above).

• Experience with Hack The Box or Capture the Flag simulations.

• Exposure to advanced testing techniques and red team engagements.

Why Join Instil?

At Instil, we believe great work starts with happy, motivated people. That’s why we’ve built a benefits package that supports your wellbeing, growth, and life outside of work, because when you thrive, so do we.

• Recognition That Matters: A discretionary annual performance bonus that rewards your impact and contribution to our success.

• Flexibility Built In: Flexible working arrangements and summer hours, because life isn’t 9 to 5, and balance matters.

• Financial Security: A highly competitive pension scheme with generous employer contributions, private healthcare, and life assurance for peace of mind.

• Health & Wellbeing: Employee Assistance Programme, mental health support, cycle‑to‑work scheme, and regular social events to keep our culture vibrant.

• Time to Recharge: 35 days holiday, enhanced maternity pay, and family‑first policies so you can focus on what matters most.

• Learning Never Stops: From courses to certifications, we’ll invest in your development so you can keep growing and shaping what’s next.

• Community & Culture: Opportunities to volunteer, give back, and be part of initiatives that make Instil a truly inclusive and connected workplace.

And that’s just the start, drop us a note to find out more.

Company Description

Instil has been delivering world‑class software engineering and technology solutions for over 20 years, trusted by global brands to solve complex challenges and drive innovation. From modernising legacy systems to building cutting‑edge applications, we help our clients navigate an ever‑changing digital landscape with confidence and agility.

We’re proud to be an award‑winning employer, reflecting how our people are at the heart of everything we do:

• Recognised as a Great Place to Work® for three consecutive years, and in 2024 ranked in the Top 20 Best Workplaces in the UK for medium‑sized companies.

• Winner of Company of the Year at the Digital DNA Awards 2022, celebrating excellence in Northern Ireland’s tech sector.

Driven by a love for technology and a commitment to excellence, we bring together people who want to make a difference. We’ll support your journey, because your success is part of ours.