Infrastructure Penetration Tester

Job Title: Senior Penetration Tester (Infrastructure Focus)
Location: London (Hybrid / Flexible)
Salary: Up to £80,000 + Bonus + Benefits
Employment Type: Permanent
Overview
We are seeking an experienced Senior Penetration Tester with a strong background in infrastructure security testing to join a growing offensive security team. The ideal candidate will have deep technical expertise, the ability to lead and independently deliver complex engagements, and a passion for uncovering and exploiting vulnerabilities across enterprise environments.
You will play a key role in strengthening the organisation's security posture by conducting infrastructure-focused assessments, mentoring junior testers, and influencing remediation strategies.
Key Responsibilities

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  Deliver internal and external network and infrastructure penetration tests, including on-premises and cloud-hosted environments
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  Perform testing of Windows & Linux infrastructure, Active Directory, network services, and security appliances
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  Conduct vulnerability exploitation, privilege escalation, and lateral movement to demonstrate full attack paths
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  Lead small engagement teams and oversee delivery quality, documentation, and client communication
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  Produce high-quality, concise, and risk-aligned reports with actionable remediation guidance
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  Support scoping calls, stakeholder workshops, and post-engagement debriefs
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  Contribute to tooling, methodology enhancement, and internal research initiatives
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  Stay up-to-date with emerging vulnerabilities, exploits, and attacker techniques

Required Skills & Experience

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  3-5+ years' professional penetration testing/offensive security experience
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  Strong understanding of enterprise infrastructure, AD security, networking, and protocols
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  Proficiency with tools such as Nmap, Nessus, Metasploit, BloodHound, Burp Suite, Kali/Linux toolsets
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  Solid track record of delivering infrastructure pentests end-to-end
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  Excellent communication skills, including producing business-focused reporting

Preferred Qualifications

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  CHECK Team Member (CSTM) or CHECK Team Leader (CTL)
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  CREST CRT/CCT, OSCP, OSEP, or equivalent recognised industry certifications
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  Experience in cloud infrastructure testing (Azure/AWS), desirable but not essential
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  SC or DV clearance beneficial (or eligibility to obtain it)

What We Offer

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  Salary up to £80,000 depending on experience + performance bonus
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  Strong personal development support - certifications funded and continuous training
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  Defined career progression into CTL or Red Team positions
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  Hybrid working with London as the preferred base