Penetration Tester

Harnham; Greater London; Remote; GBP 92,000 - 101,000; Full time

Job summary

Harnham is seeking a Penetration Tester to work remotely with occasional travel to the Battersea office. You will own end-to-end infrastructure and network penetration engagements, assessing complex architectures and communicating findings to stakeholders across regions.

The role offers a £500–£550 per day rate outside IR35 with a December start. The successful candidate will lead testing programs, produce technical reports, and contribute to maturing the internal security testing capability in

Qualifications

• Experience delivering infrastructure and network penetration testing engagements.
• Ability to scope testing activities and communicate findings to stakeholders.
• Strong report-writing and client-facing communication skills.

Responsibilities

• Lead end-to-end infrastructure and network penetration testing engagements.
• Assess enterprise network architectures and identify weaknesses beyond basic scans.
• Test across complex environments and security boundaries.
• Engage with stakeholders to scope activities and communicate findings.
• Produce clear technical reports and remediation recommendations.

Skills

Infra & Network Pentest

Lifecycle management

Stakeholder communication

Report writing

Client-facing

Team collaboration

Job description

PENETRATION TESTER

REMOTE (OCCASIONAL TRAVEL TO OFFICE IN BATTERSEA)

OUTSIDE IR35

£500 TO £550 PER DAY

DECEMBER START

This is an opportunity to join a growing in-house cyber security function that is continuing to expand its penetration testing capability across multiple business units. You'll take ownership of end-to-end testing engagements, working independently while helping shape the future direction of a mature and evolving security programme.

The Company

They are a large international organisation with a diverse portfolio of consumer-focused businesses operating across multiple regions. Over recent years, they have invested significantly in building internal cyber security capabilities, creating a consultancy-style function that supports a broad range of technology environments. Their security team works closely with stakeholders across Europe and Asia, delivering high-quality testing and security assurance services.

The Role and Deliverables

• Lead and deliver end-to-end infrastructure and network penetration testing engagements.
• Perform in-depth assessments of enterprise network architectures and identify security weaknesses beyond standard vulnerability scanning.
• Conduct security testing across network boundaries and complex infrastructure environments.
• Engage directly with stakeholders to scope testing activities and communicate findings.
• Produce clear technical reports and present remediation recommendations to both technical and non-technical audiences.
• Contribute to the ongoing development and maturity of the internal security testing capability.

Your Skills & Experience

• Strong experience delivering infrastructure and network penetration testing engagements.
• Proven capability in assessing complex network architectures and identifying exploitable weaknesses.
• Experience managing the full penetration testing lifecycle independently, from scoping through to reporting.
• Ability to communicate technical findings and recommendations clearly to a range of stakeholders.
• Strong client-facing and report-writing skills.
• Experience working across large, complex environments with multiple stakeholders.
• Exposure to Operational Technology (OT) security testing would be advantageous.
• Experience within telecommunications, retail, critical infrastructure, or similarly complex environments would be beneficial.
• Comfortable collaborating with international teams across different regions and time zones.

Desired Skills and Experience

Infrastructure & Network Penetration Testing, Network Architecture Assessments, End-to-End Penetration Testing, Vulnerability Identification & Exploitation, Security Reporting, Stakeholder Management, Technical Presentations, Enterprise Network Security, Risk Assessment, Consultancy-Style Security Testing, OT Security (desirable), Telecommunications/Retail Security (desirable).