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Senior Penetration Tester (CTL / CSTL) | CHECK | Remote (UK)

Optimal
Department:Technical Support
Type:REMOTE
Region:UK
Location:London Area, United Kingdom
Experience:Mid-Senior level
Salary:£80,000 - £100,000
Skills:
PENETRATION TESTINGCHECK CERTIFICATIONCTLCSTLSC CLEARANCEINFRASTRUCTURE PENETRATION TESTINGAPPLICATION PENETRATION TESTINGOFFENSIVE SECURITYVULNERABILITY ASSESSMENTTHREAT MODELLINGRISK ASSESSMENTCLIENT-FACINGREPORTINGAWSAZURECLOUD SECURITYRED TEAMINGAUTOMATIONTOOLING
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Job Description

Posted on: December 11, 2025

Senior Penetration Tester (CTL / CSTL) | CHECK | Remote (UK) | 20% TravelLocation: United Kingdom (Fully Remote) - Travel across the UK (approx. 20%), fully expensed

Package:£80,000 – £100,000 base salary + Excellent Benefits

Eligibility: Must hold UK residency + valid SC Clearance and CHECK certification (CTL or CSTL)

Travel: Role includes up to 15/20% UK travel to client sites across The UK (all expenses covered)

🚨 Please only apply if you have ALL the following 🚨

  • 6+ years’ hands-on penetration testing experience
  • Current CTL or CSTL status (held for 2+ years)
  • Active SC Clearance
  • CHECK certification (CTL / CSTL / CSTM - you must hold CHECK status, we will verify)
  • Strong track record delivering advanced pen testing across infrastructure and/or applications
  • Ability to work independently in senior-level client-facing environments
  • Willingness to travel approximately 15/20% across the UK

Required Background

  • 6+ years’ industry experience in offensive security / penetration testing
  • Demonstrable depth in at least one of the following:
  • Infrastructure Pen Testing
  • Application / Web App Pen Testing
  • Strong knowledge of modern attack techniques, tooling, and methodologies
  • Experience delivering reports, presenting findings, and advising on remediation
  • Exposure to large-scale enterprise, government, or regulated environments
  • Ability to run complex engagements end-to-end with minimal oversight
  • Clear understanding of threat modelling, risk assessment, and senior stakeholder communication

ℹ️ Very Important Notes

  • You MUST hold CTL or CSTL status (CHECK-approved)
  • You MUST hold SC Clearance
  • This is a senior, hands-on role - not suitable for juniors or mid-level testers
  • The role includes UK-wide travel (approx. 20%), fully expensed
  • Dual-skilled CTLs (Infrastructure + Apps) will be considered for the top salary band
  • Strong communication and client-facing professionalism is essential

Must-Haves (Non – negotiable)

  • CTL or CSTL status held for minimum 2 years
  • CHECK registration (CTL / CSTL / CSTM — must confirm you hold CHECK status)
  • Deep technical proficiency in offensive security
  • Ability to scope, plan, execute, and deliver high-quality testing engagements
  • Strong reporting, documentation, and advisory capabilities
  • Experience working with enterprise or government clients
  • SC Cleared
  • UK-based and eligible to work & travel freely
  • Stable career history and proven delivery of long-term engagements

Bonus Experience

  • Dual-skilled CTL (Infrastructure + Applications)
  • Experience mentoring or guiding junior testers
  • Red Teaming exposure
  • Experience with tooling and automation for testing
  • Knowledge of cloud security (AWS/Azure)
  • Threat intelligence or purple team collaboration experience

Hands-On Experience With

  • Infrastructure penetration testing
  • Web and application penetration testing
  • Advanced exploitation, enumeration, and privilege escalation
  • Reporting to CHECK standards
  • Vulnerability assessment tooling
  • Manual testing methodologies aligned to industry best practice
  • Working with clients across public sector, enterprise, or highly regulated industries

What You’ll Be DoingPen Testing & Delivery

  • Deliver high-quality penetration testing engagements (infrastructure, applications, cloud etc.)
  • Execute senior-level testing aligned to CHECK requirements
  • Provide in-depth, quality reporting with remediation guidance
  • Lead or contribute to multi-scope testing assignments

Quality & Ownership

  • Ensure testing is delivered to the highest technical and professional standard
  • Maintain CHECK-level methodologies and best practices
  • Support continuous improvement in offensive security approaches

Client Interaction

  • Present findings and recommendations to technical and non-technical stakeholders
  • Work directly with engineering, security, and leadership teams
  • Provide expert guidance, advisory support, and risk insight

If you meet all the above essentials and are a highly capable Senior Penetration Tester with CTL/CSTL and SC, get in touch for an immediate conversation.

Originally posted on LinkedIn

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