Penetration Tester (Infrastructure)

JR United Kingdom; City Of London; On-site; GBP 55,000 - 80,000; Full time

Job summary

A leading company in the digital security domain is seeking an experienced Infrastructure Penetration Tester to join their high-performing team in London. The role involves conducting hands-on testing in complex environments, with responsibilities that include internal assessments and client interfacing. Ideal candidates should possess a strong background in penetration testing and hold relevant certifications, while thriving in a technically challenging environment.

Qualifications

• At least 4 years’ experience in infrastructure penetration testing.
• Strong knowledge of Active Directory exploitation techniques.
• Command-line skills across Windows and Linux systems.

Responsibilities

• Conduct internal infrastructure and Active Directory penetration tests.
• Produce clear, concise reports for technical and non-technical audiences.
• Build trusted relationships with clients.

Skills

Active Directory exploitation techniques

Command-line skills

Python scripting

Operational Technology (OT) networks

Internal infrastructure exploitation tools

Job description

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Penetration Tester (Infrastructure), london (city of london)

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Client:

Anson McCade

Location:

london (city of london), United Kingdom

Job Category:

Other

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EU work permit required:

Yes

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Job Views:

4

Posted:

26.06.2025

Expiry Date:

10.08.2025

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Job Description:

Note: To be eligible for this role, you must be eligible for UK Security Clearance (SC).

A high-performing digital security team is looking for an experienced Infrastructure Penetration Tester to join them in delivering critical assessments across complex and sensitive client environments.

This is a hands-on internal testing role, not web application focused, where you'll be expected to work independently and navigate challenging systems with confidence.

This role is suited to testers who thrive in technically demanding scenarios, want autonomy, and are motivated by work with real-world impact.

Key Responsibilities

• Conduct internal infrastructure and Active Directory penetration tests in live production environments
• Produce clear, concise reports tailored to both technical and non-technical audiences
• Build trusted relationships with clients in a consultancy-facing capacity
• Work within a small, high-trust team on sensitive engagements
• Contribute to the evolution of internal tooling and testing methodologies
• Operate effectively in environments with limited documentation or predefined processes

Essential Experience and Skills

• At least 4 years’ experience in infrastructure penetration testing
• Strong knowledge of Active Directory exploitation techniques (privilege escalation, lateral movement, etc.)
• Strong command-line skills across Windows and Linux systems
• Ability to work through legacy systems, unpatched software, and environments with technical debt
• Python scripting or automation experience
• Understanding of Operational Technology (OT) networks
• Familiarity with internal infrastructure exploitation tools

Certifications (preferred but not essential):

• CREST CTM, CTL, CSTM or Cyber Scheme Practitioner
• OSCP (current or lapsed)

If you’re an experienced infrastructure penetration tester looking for meaningful work, we want to hear from you.