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

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

Required Skills & Experience

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

Preferred Qualifications

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

What We Offer

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