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Posted on 2025/12/11

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

Optimal

United Kingdom

Full-time

Full Description

Senior Penetration Tester (CTL / CSTL) | CHECK | Remote (UK) | 20% Travel

Location: 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 Doing

Pen 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.

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