About The Role

The primary function of the Penetration Tester in the CST team is to continually review the customers’ defined scope for vulnerabilities, identify additional targets that should be included in the scope, and report these to the client in a timely, accurate, and comprehensive manner. The Penetration Tester is also responsible for pre-engagement activities including scoping, statements of work, working with customers to determine their testing requirements and restrictions, on boarding customers into the service and contribute to the service improvement and further development.

Essential duties & responsibilities

The Continuous Security Testing service is a consultant led vulnerability identification and verification service which makes use of automated vulnerability scanning along with significant manual testing against a broad scope in a continuing engagement. The purpose of the service is to continually monitor a customer’s external attack surface for new vulnerabilities, changes in the scope of the attack surface, and proactively inform customers of discovered issues along with recommended remediation; with the overall aim of reducing the lifetime of each vulnerability. Manual testing includes identification of issues which automation alone could not identify, exploitation of all issues, often chaining multiple findings together in order to determine the true impact of vulnerabilities for the customer.

  • Pre-engagement activities including scoping of assessments and statements of work and determining customer requirements and restrictions.
  • On boarding customers into the service including configuration of continual scanning and liaising with customer to resolve issues which may reduce the effectiveness of scanning.
  • Monitoring of the customers’ external perimeter for changes, and proactive discovery of new targets to include within the customer’s scope.
  • Manual identification and exploitation of vulnerabilities.
  • Manual verification and exploitation of scanner findings.
  • Detailed analysis of issues identified and exposure for the customer including proof of concept, reproduction steps, and recommended remediation.
  • Communication of findings to the customer in a detailed, accurate and manageable manner both orally and through written vulnerability/scope notifications and periodic summaries.
  • Assisting in the continual development of the team and service through research and development activities. This includes the development of in-house tools the implementation of tools released to the community, and design and documentation of new and existing internal systems and processes.
  • Continual professional development to maintain and develop knowledge and technical competencies.
  • Maintain professional technical qualifications to demonstrate competency to our clients.
  • Contributing to the writing and publishing of whitepapers and advisories.
  • Undertaking projects and support tasks as appropriate to the role.

About You


  • Excellent written and spoken English including presentation, structure, spelling, and grammar. Along with experience conveying technical information in an accessible manner.
  • Core computing skills including but not limited to:
    • Networking fundamentals – understanding of OSI Model, TCP/IP, HTTP, DNS, SMB, SMTP and relevant tools.
    • Microsoft Windows and Office proficiency along with proficiency in one or more Linux distributions.
  • Strong knowledge of web application technologies and security assessment including but not limited to:
    • REST APIs, SOAP APIs, XML and JSON formats.
    • Vulnerability identification and exploitation (not limited to OWASP Top 10).
    • Experience with common assessment tools such as MITM proxies (e.g. Burp Suite Pro) and SQLMap.
  • Good knowledge of internal and external infrastructure technologies and security assessment including but not limited to:
    • Identification and exploitation of misconfigurations or known vulnerabilities in common enterprise infrastructure and services (Windows Domains, Linux servers, virtualisation, databases, switches/routers, etc).
    • Windows and Linux Sandbox/Desktop Breakout.
  • Knowledge of a scripting language such as Python (preferred), Ruby, PowerShell, or Bash, for the development of new, or editing existing, tools.
  • Evidence of rapidly and confidently gaining knowledge of, and applying knowledge of, emerging technologies, vulnerabilities, and penetration testing tools and techniques.
  • Excellent time management including setting priorities and goals to complete assigned and arising tasks.


  • Knowledge of Open Source Intelligence gathering techniques. Including but not limited to use of Google dorks, DNS, domain registration, certificate transparency, and other public sources of information.
  • Experience with live bug bounties, particularly where automation has been implemented.
  • Knowledge of security considerations in the cloud (AWS, Azure, and GCP), particularly identifying vulnerable configurations through management and API access along with exploitation of web/infrastructure vulnerabilities specific to cloud environments.
  • Knowledge of mobile application vulnerability identification and exploitation including but not limited to Android and iOS app structure, decompliation, code signing, and traffic interception.

Desirable Certifications

  • CRT - CREST Registered Penetration Tester (or above).
  • OSCP – Offensive Security Certified Professional.
  • GWAPT – GIAC Web Application Penetration Tester.
  • A related Bachelor’s degree.

About Us

Claranet is one of Europe’s leading managed IT services providers that is growing both organically and through acquisition. We offer businesses hosting, networks and communications services and have revenues of £310m, over 6,500 customers and an outstanding record for delivering high quality solutions, across a wide range of industries.  With over 1,800 employees, we are based in 24 offices across Europe and in Brazil.


Sec-1 is a Claranet Group Company, established since 2001 and now providing professional standard Information Security Solutions to over 600 customers across Public and Private sectors. Sec-1 Ltd’s Continuous Security Testing (CST) team is composed of highly skilled penetration testers with a real passion for improving system security posture by demonstrating how they can be broken. Team members work on everything from customer projects to community work to gaining credit for published advisories. Our team needs to grow, we are producing amazing results that make a real difference, and if you can help make this difference you should come join us too.

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