Infrastructure Penetration Tester

Digital Waffle; City Of London; Hybrid; GBP 68,000 - 80,000; Full time

Job summary

A growing security firm in London seeks an experienced Senior Penetration Tester to enhance security posture through infrastructure assessments. The role offers a salary of up to GBP80,000 based on experience and a performance bonus. You will lead penetration tests, mentor junior staff, and contribute to security methodologies. Hybrid working is available, with London as the preferred base.

Benefits

Performance bonus

Strong personal development support

Defined career progression

Hybrid working

Qualifications

• 3-5+ years of professional penetration testing experience.
• Strong understanding of enterprise infrastructure and networking.
• Proficiency with various security testing tools.

Responsibilities

• Deliver and oversee network and infrastructure penetration tests.
• Conduct vulnerability exploitation and privilege escalation.
• Produce high-quality reports with actionable remediation guidance.

Skills

Penetration testing

Infrastructure security

Windows & Linux

Active Directory

Networking and protocols

Communication skills

Tools

Nmap

Nessus

Metasploit

BloodHound

Burp Suite

Kali/Linux toolsets

Job description

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 GBP80,000 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