Penetration Tester

Posted 8 Days Ago
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London, Greater London, England, GBR
Hybrid
50K-58K Annually
Entry level
Professional Services • Consulting • Financial Services
The Role
Conduct client-facing penetration tests across web applications, APIs, and network infrastructure. Perform Cyber Essentials Plus assessments, vulnerability assessments, cloud security reviews, and configuration reviews. Identify and validate vulnerabilities, communicate business risks, produce technical reports, and advise on remediation. Manage testing scopes and client engagements while contributing to advisory work, business development, methodology improvements, peer review, and security practice growth.
Summary Generated by Built In
Moore Kingston Smith is seeking an experienced penetration tester to join our NCSC-recognised cyber security team within our Risk Advisory practice, supporting a diverse portfolio of clients across multiple sectors.
This is a hands-on role focused on delivering penetration tests across web applications, APIs, and internal and external network infrastructure. You will also support Cyber Essentials Plus assessments and wider technical security reviews, including vulnerability assessments, configuration reviews against recognised benchmarks, and cloud security reviews. You will identify and safely validate security weaknesses, explain the associated business risks clearly, and provide practical remediation advice tailored to each client.
We are looking for an individual with strong technical fundamentals, sound professional judgement and a genuine interest in helping clients improve their security posture. Alongside developing your offensive security expertise, you will have the opportunity to contribute to the growth of the cyber security practice and increasingly take ownership across technical delivery, knowledge-sharing and the development of our services. While technical delivery will remain the core focus, if interested, you will also have the opportunity to contribute to broader cyber security engagements, including cyber maturity assessments, security control reviews, audit readiness activities and security design advisory work.

Key Responsibilities
  • Lead and support penetration testing engagements across web applications, APIs, and internal and external network infrastructure. 
  • Work with clients to define objectives, agree scope and rules of engagement, and plan testing that meets their assurance needs.
  • Apply manual and tool-assisted testing techniques aligned with recognised methodologies and frameworks, including the OWASP Web Security Testing Guide, PTES, and MITRE ATT&CK.
  • Deliver Cyber Essentials Plus assessments, including scoping, conducting the required technical tests, verifying remediation and supporting clients through to certification in line with current NCSC and IASME scheme requirements.
  • Deliver wider technical security assessments, including vulnerability assessments, cloud security reviews, and build and configuration reviews against CIS Benchmarks and vendor hardening guidance.
  • Produce clear, high-quality deliverables and present findings to technical and non-technical stakeholders. Apply appropriate risk ratings, explain business impact, and support clients with remediation and retesting.
  • Support general advisory engagements such as cyber risk assessments, security control reviews, audit readiness, remediation planning and security design advice.
  • Build strong client relationships and contribute to business development, supporting proposals, scoping, tenders and thought leadership, and identifying opportunities to expand our services.
  • Maintain current knowledge of the threat landscape, emerging attack techniques, testing methodologies, and scheme requirements, while contributing to peer review and quality assurance.
  • Contribute to the continuous improvement of our methodologies, tooling, delivery processes, and technical capability.

Skills, Knowledge and Expertise
Essential
  • Professional experience delivering client-facing penetration tests across web applications, APIs, and internal or external network infrastructure, independently and/or as part of a team. 
  • Strong manual testing capability and sound judgement in selecting and using automated tools, with practical experience of Kali Linux, Burp Suite, Nmap, and Qualys or Nessus.
  • Familiarity with recognised penetration testing methodologies and frameworks, together with the ability to script or automate tasks using Python, PowerShell, Bash, or a comparable language.
  • Good knowledge of modern web architecture, common web and API vulnerabilities, TCP/IP, Windows and Linux security, and Active Directory and Microsoft Entra ID attack paths.
  • Experience delivering, or the ability to deliver, wider technical assessments such as vulnerability assessments and configuration reviews against recognised benchmarks such as CIS.
  • Working knowledge of the Cyber Essentials and Cyber Essentials Plus schemes. Existing assessor experience is beneficial; appropriate training will be provided where required.
  • Ability to manage engagements within agreed scope, rules of engagement, timescales, budget, and quality standards, while maintaining clear testing evidence and protecting client systems and data.
  • Strong written communication skills, including the ability to produce clear, accurate, and actionable technical reports.
  • Strong verbal communication and stakeholder-management skills, with the ability to explain technical findings, risk, and business impact to technical and non-technical audiences.
  • A proactive, client-oriented mindset and a commitment to continuous learning, confident working with clients ranging from SMEs and scale-ups to larger enterprises.
Desirable
  • A recognised practical penetration testing certification, such as CREST CRT, OSCP, OSWE, CSTM or an equivalent qualification.
  • Experience in additional testing disciplines such as mobile application, wireless or cloud penetration testing, or phishing and social-engineering assessments.
  • Experience with public cloud and SaaS platforms such as AWS, Azure, GCP or Microsoft 365, or hands-on security or IT engineering experience such as hardening systems and implementing technical controls.
  • An interest in, or experience of, broader advisory work such as cyber risk assessments, security control reviews, audit readiness, or working knowledge of a recognised framework such as ISO/IEC 27001, NIST, or CIS Controls.

Benefits


About
At Moore Kingston Smith, we believe in the potential of people to make a positive impact, fuelled by the power of genuine understanding. Working with small, medium and large clients, we are a multi-disciplinary advisory, tax and audit firm with expertise across multiple sectors, uniquely positioned to help people realise their ambitions. Our London and regional teams deliver quality results locally and nationally, and worldwide alongside the Moore Global network. Through respect, collaboration and active listening, understanding is at the heart of everything we do with our clients, colleagues and communities. We value people and projects that promote positive change for the future. Come and join us to make a difference.

Skills Required

  • Professional experience delivering client-facing penetration tests across web applications, APIs, and internal or external network infrastructure
  • Strong manual testing capability and practical experience with Kali Linux, Burp Suite, Nmap, and Qualys or Nessus
  • Familiarity with recognized penetration testing methodologies and frameworks
  • Ability to script or automate tasks using Python, PowerShell, Bash, or a comparable language
  • Knowledge of modern web architecture, web and API vulnerabilities, TCP/IP, Windows and Linux security, Active Directory, and Microsoft Entra ID attack paths
  • Experience delivering or ability to deliver vulnerability assessments and configuration reviews against recognized benchmarks such as CIS
  • Working knowledge of Cyber Essentials and Cyber Essentials Plus schemes
  • Ability to manage engagements within scope, rules of engagement, timescales, budget, and quality standards
  • Strong written communication skills for producing clear, accurate, and actionable technical reports
  • Strong verbal communication and stakeholder-management skills
  • Proactive, client-oriented mindset and commitment to continuous learning
  • Recognized practical penetration testing certification such as CREST CRT, OSCP, OSWE, CSTM, or equivalent
  • Experience with mobile application, wireless, cloud penetration testing, phishing, or social-engineering assessments
  • Experience with AWS, Azure, GCP, Microsoft 365, or hands-on security and IT engineering
  • Interest or experience in cyber risk assessments, security control reviews, audit readiness, ISO/IEC 27001, NIST, or CIS Controls
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The Company
HQ: London
988 Employees
Year Founded: 2006

What We Do

Moore Kingston Smith is a multi-disciplinary advisory, tax, and audit firm with expertise across multiple sectors, uniquely positioned to help people realize their ambitions.

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