Lead Penetration Tester

JR United Kingdom; Slough; Hybrid; GBP 60,000 - 85,000; Full time

Job summary

A leading consultancy in the UK is seeking a Senior Consultant to Principal Consultant specializing in infrastructure penetration testing. This is a fantastic opportunity to work on mission-critical projects across defense and operational technologies, utilizing your skills to enhance security in complex environments. You will be part of a high-trust team focused on real-world impact and supported by a flexible hybrid working model.

Benefits

High-trust culture

Flexible hybrid model

Support for client needs with on-site flexibility

Tight-knit, high-performing team

Qualifications

• 4+ years of experience in penetration testing with a focus on infrastructure.
• Strong expertise in Active Directory and privilege escalation.
• Familiarity with operational technology and complex network environments.

Responsibilities

• Deliver end-to-end infrastructure testing across sensitive environments.
• Identify vulnerabilities with minimal documentation.
• Communicate technical findings to stakeholders.

Skills

Penetration Testing

Active Directory Attacks

Lateral Movement

Privilege Escalation

Python Scripting

Operational Technology Networks

Communication Skills

Tools

CrackMapExec

BloodHound

PowerView

Job description

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? Location: London preferred (Hybrid)

? Level: Senior Consultant to Principal Consultant (SC–PC)

Flexible hybrid model | High-trust culture | Mission-critical work

? The Opportunity

Join a high-impact consultancy at the forefront of innovation and digital transformation. You’ll be part of a specialist team delivering critical infrastructure penetration tests across some of the most sensitive environments in the UK — from defence and national security to critical infrastructure and operational technology.

This is not a web application role. We’re looking for an infrastructure-focused penetration tester with the technical confidence and consultancy mindset to work independently, lead engagements, and deliver real-world impact.

If you want to push beyond checklists and automated scans and into deep, hands-on testing — this is the place to do it.

? What You’ll Be Doing

• Deliver end-to-end infrastructure and internal network testing (Active Directory, internal corporate networks, etc.)
• Identify and exploit vulnerabilities across complex environments with minimal documentation
• Communicate technical findings through clear written reports and debriefs to a range of stakeholders
• Support sensitive clients operating in production environments — where mistakes matter
• Contribute to tooling, methodologies, and continuous improvement of team capability
• Engage with a technical and non-technical audience, acting as a trusted security advisor

? What You Bring

Core Skills:

• 4+ years of penetration testing experience (infrastructure/internal focus)
• Strong hands-on expertise with Active Directory attacks, lateral movement, and privilege escalation
• Experience navigating live and legacy production systems
• Comfortable in Windows and Linux command-line environments
• Python scripting or automation experience
• Familiarity with OT (Operational Technology) networks
• Experience with tools like CrackMapExec, BloodHound, PowerView, etc.

Certifications (a bonus, not a barrier):

• OSCP
• Lapsed certifications are fine if practical skills are strong
• Tight-knit, high-performing team (2–3 people) with deep trust and autonomy
• Remote-first culture (approx. 80% remote) with flexibility for client needs (up to 2 days per week on-site if required)
• Fast-paced environment with complex technical challenges
• Expect to hit the ground running – support is there, but this is a role for a self-starter