Principal Penetration Tester

Instil, Belfast, Northern Ireland, United Kingdom

Join our dynamic security team as a senior, hands‑on Principal Penetration Tester with CHECK Team Lead (CTL) status. In this role you will lead and deliver complex penetration testing engagements across infrastructure, cloud, web, and mobile applications for a diverse range of clients.

• 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.

• 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 the ability to perform cloud security reviews.
• Proficiency with tools such as Burp Suite Pro, Nmap, Nessus, Metasploit, and Kali Linux.
• Strong scripting skills (Python, Shell, etc.).
• Excellent communication and technical report writing skills.

• 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.

• Recognition That Matters: A discretionary annual performance bonus that rewards your impact.
• Flexibility Built In:
  Flexible working arrangements and summer hours.
• Financial Security:
  Highly competitive pension scheme, private healthcare, and life assurance.
• Health & Wellbeing:
  Employee Assistance Programme, mental health support, cycle‑to‑work scheme, and regular social events.
• Time to Recharge: 35 days holiday, enhanced maternity pay, and family‑first policies.
• Learning Never Stops:
  From courses to certifications, we invest in your development.
• Community & Culture:
  Opportunities to volunteer, give back, and be part of inclusive initiatives.

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. We help clients navigate an ever‑changing digital landscape with confidence and agility.

We’re proud to be an award‑winning employer: recognized 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.

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.

Seniority level: Mid‑Senior level

Employment type: Full‑time

Job function: Information Technology

Industries: Software Development

Referrals increase your chances of interviewing at Instil by 2x