Penetration Tester - Vulnerability Researcher

Thales Group; Doncaster; On-site; GBP 66,000 - 106,000; Full time

Benefits offered by this job

Performance-related bonus

Half day Fridays

28 days annual leave + bank holidays

Paid volunteering 24 hours

Private healthcare

Pension scheme

Life cover

Employee Assistance Program

Mental wellbeing app access

Employee discounts

Gym membership discounts

Job summary

Thales Group in the United Kingdom is seeking a hands-on penetration tester to cover Windows, Linux, mobile, web, and cloud environments. You will identify vulnerabilities, produce clear reports, and support high-security accreditation programmes.

The role requires CSTL certification and a strong grasp of testing methodologies, with a pathway toward technical leadership. UK national with SC clearance is required.

Qualifications

• Hands-on penetration testing across IT and/or OT environments.
• Degree in Computer Science, Engineering, or equivalent experience.
• Strong understanding of security testing methodologies and frameworks.
• Experience producing clear, actionable technical reports.
• Industry certifications such as CREST, OSCP, CEH, GPEN, GXPN desirable.
• Background in Defence, Aerospace, Government, Nuclear, Transport or other regulated industries desirable.
• Familiarity with compliance-driven environments and secure system accreditation desirable.
• UK National and ability to obtain Security Clearance (SC) without caveats.

Responsibilities

• Penetration testing across Windows, Linux, mobile (iOS/Android), web applications and cloud environments.
• Identify, exploit and clearly communicate security vulnerabilities and risks.
• Support accreditation and assurance activities on complex, high-security programmes.
• Advise on security controls and mitigation strategies aligned to customer needs.
• Contribute to governance frameworks, policies and secure operating procedures.
• Produce high-quality technical reports and through-life security documentation.
• Act as cybersecurity SMEs across projects and stay aligned with evolving regulations and standards.
• Collaborate with internal teams, customers and external stakeholders at all levels.
• Support bid activities, including technical input and effort estimation.

Skills

Penetration testing

Security reporting

Security frameworks

Stakeholder collaboration

Secure operating procedures

Education

Bachelor's degree in Computer Science, Engineering, or equivalent

Tools

Android

iOS

Linux

Windows

Cloud

Web

Job description

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.

• 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
• gym membership discounts

We are committed to equal opportunities, inclusive working, and creating a workplace where everyone feels valued.

last updated 37 week of 2026