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SR2 | Socially Responsible Recruitment | Certified B Corporation™
Infrastructure Penetration Tester | CHECK | Crest | CSTL/CTL | Networking | Config

Infrastructure Penetration Tester | CHECK | Crest | CSTL/CTL | Networking | Config

On site

London, United kingdom

Freelance

16-10-2025

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Skills

Communication Penetration Testing Firewalls Configuration Management Security Testing Networking api testing

Job Specifications

Infrastructure Penetration Tester | CHECK | Crest | CSTL/CTL | Networking | Config Reviews | API Testing | Contract
Pen Testing | Infrastructure | External & Internal Networks

SR2 is partnered with a leading security consultancy on a significant multi-phase testing programme, and we're looking for an experienced Infrastructure Penetration Tester to join the team.
This role will focus on delivering hands-on penetration testing across external and internal networks, reviewing system configurations, and identifying vulnerabilities within critical infrastructure. You'll work alongside a small team of experienced testers to support a major client undergoing large-scale change, ensuring their environment is secure and compliant.

Key Responsibilities:
Conduct comprehensive external and internal infrastructure penetration tests, starting with perimeter systems and moving into internal networks
Perform configuration reviews across Servers, Firewalls, Routers, and network devices
Execute API security testing to assess authentication, data access, and integration risks
Deliver "old-school" CHECK-style network and infrastructure testing in line with industry standards
Produce detailed technical reports outlining vulnerabilities, exploitation paths, and remediation guidance
Collaborate with the project lead and wider team across a six-phase testing programme
Engage directly with stakeholders and SMEs to ensure smooth onboarding and deliverySkills & Experience Required:
Proven background in infrastructure penetration testing within complex network environments
Crest certification or CHECK Team Member/CHECK Team Lead (CTM/CTL) status advantageous
Strong understanding of networking, configuration management, and common attack vectors
Experience performing API and configuration reviews
Excellent report writing and communication skills for both technical and non-technical audiences
Ability to work on-site in London for key phases of testing
Collaborative mindset, comfortable working as part of a small testing team (3-4 people)The Details:

Contract role - IR35 Outside
Rate: market rate
Location: West London
Start: Within 2-3 weeks
Length: 6 monthsIf you're am Infrastructure penetration tester with experience across networks, configurations, and APIs, and you're looking for a hands-on role in a collaborative team delivering a major London-based project, apply now for immediate consideration.

About the Company

Built to Make an Impact. We exist to harness the power of recruitment to create meaningful change across the world. Our mission is simple but profound: to connect purpose-driven talent with industries that shape a better future. From driving innovation in Tech for Impact, advancing the global Clean Energy transition, to empowering Central Government Public Services, we are a Global Recruitment Group committed to making an impact and leaving a positive legacy. Why We Exist We believe recruitment should do more than fil... Know more