Penetration Tester - Vulnerability Researcher

Salary: £66,000 - 106,000 per year

Requirements:

• We are looking for hands-on penetration testing experience across diverse platforms, including IT and/or OT environments.
• We require CSTL (Cyber Scheme Team Leader) certification.
• We are looking for a strong understanding of security testing methodologies and frameworks.
• We require experience producing clear, actionable technical reports.
• We are looking for a degree in Computer Science, Engineering, or equivalent experience.
• Industry certifications such as CREST, OSCP, CEH, GPEN, GXPN, or similar are desirable.
• Background in Defence, Aerospace, Government, Nuclear, Transport, or other regulated industries is desirable.
• Familiarity with compliance-driven environments and secure system accreditation is desirable.
• This role requires you to be a UK National and achieve Security Clearance (SC) without any caveats.

Responsibilities:

• We conduct penetration testing across Windows, Linux, mobile (iOS/Android), web applications, and cloud environments.
• We identify, exploit, and clearly communicate security vulnerabilities and risks.
• We support accreditation and assurance activities on complex, high-security programmes.
• We advise on security controls and mitigation strategies aligned to customer needs.
• We contribute to governance frameworks, policies, and secure operating procedures.
• We produce high-quality technical reports and through-life security documentation.
• We act as cybersecurity SMEs across projects, staying aligned with evolving regulations and standards.
• We collaborate with internal teams, customers, and external stakeholders at all levels.
• We support bid activities, including technical input and effort estimation.

Technologies:

• Android
• Cloud
• Support
• Linux
• Mobile
• Security
• Web
• Windows
• iOS

More:

We are Thales, a global technology leader with more than 83,000 employees across five continents and over 7,500 people in the UK, working across defence, space, aerospace, and digital security. Based in Crawley, we are expanding our Cyber Security capability across critical national infrastructure, defence, and aerospace programmes. This is a full-time opportunity to work on mission-critical systems, with clear pathways into technical leadership or people management. Our benefits include a performance-related bonus, a half day every Friday, 28 days annual leave plus bank holidays with the option to buy extra time, 24 hours of paid volunteering, private healthcare, a pension scheme, life cover, an Employee Assistance Program, mental wellbeing app access, employee discounts, and gym membership discounts. We are committed to equal opportunities, inclusive working, and creating a workplace where everyone feels valued.

last updated 36 week of 2026