Senior Penetration Tester

London Stock Exchange Group; London; On-site; GBP 60,000 - 80,000; Full time

Job summary

A leading financial markets infrastructure provider in London is seeking a Senior Penetration Tester to conduct in-depth security testing across applications and infrastructure. The ideal candidate will have extensive experience in penetration testing, excellent reporting skills, and knowledge of cloud environments. This role offers unique opportunities for growth in a dynamic and collaborative culture.

Benefits

Healthcare

Retirement planning

Paid volunteering days

Wellbeing initiatives

Qualifications

• Proven hands-on experience in penetration testing of web applications and APIs.
• Ability to write clear, technical reports and communicate findings effectively.
• Experience with cloud platforms like AWS, Azure, or GCP.

Responsibilities

• Conduct in-depth penetration tests on applications and infrastructure.
• Document findings clearly and provide actionable remediation guidance.
• Develop and maintain custom tools and scripts to support testing activities.

Skills

Penetration testing

Web Application Security

API Testing

Cloud Security

Scripting

Technical Reporting

Interpersonal Skills

Education

Relevant security certifications

Tools

Burp Suite

Docker

Kubernetes

Job description

LSEG is seeking a Senior Penetration Tester to join our internal offensive security team. This role is hands-on and deeply technical, responsible for planning and driving penetration tests across a wide range of systems and applications. The successful candidate will be a skilled offensive security professional with a passion for uncovering vulnerabilities and improving security posture through thorough testing and teamwork.

Key Responsibilities

• Conduct in-depth penetration tests on applications, infrastructure, and cloud environments.
• Take full ownership of assigned penetration testing engagements end-to-end and deliver with limited oversight.
• Compile technical scoping documents, track and document assessment metadata
  • Engagement details (who, what, when, where)
  • Testing team members and roles
  • Tools and methodologies used
  • Schedule and timelines
  • Target systems and environments
  • Constraints, exclusions, and limitations
  • Testing activities and event logs
• Document findings clearly and concisely, providing actionable remediation guidance.
• Collaborate with application teams to scope, perform, and report on security assessments.
• Contribute to team improvement efforts and ensure all initiatives and feedback are well documented for future references.
• Contribute to the continuous improvement of testing methodologies, tooling, automation.
• Stay ahead of emerging threats, vulnerabilities, and offensive security techniques.
• Participate in R&D initiatives as guided from leadership.
• Support educational sessions and mentoring within the team.
• Develop and maintain custom tools, scripts, and exploits to support testing activities.

Required Skills & Experience

• Proven hands-on experience in penetration testing of Web Applications, APIs, Thick Client and Common Infrastructures (Active Directory, Cloud and Cloud-native based environments).
• Proficiency with tools such as Burp Suite, common command-line tools, and ability to write custom scripts when needed.
• Experience in automating pentesting tasks.
• Solid understanding of application security, network protocols, and operating systems.
• Experience with cloud platforms (AWS, Azure, GCP) and containerized environments (Docker, Kubernetes).
• Ability to write clear, technical reports and communicate findings to both technical and non-technical customers.
• Experience working in large, sophisticated enterprise environments.
• Proficient interpersonal skills in English, both written and verbal.
• Relevant certifications and engagement with the security community is a plus
• Threat Modelling experience is a plus.
• Experience working in large, sophisticated enterprise environments.
• Proven track record of successfully managing and driving security engagements for various organizations with differing operational and technical profiles.
• Ability to identify, assess, and communicate technical and project risks to partners.
• Understanding project requirements and aligning results with agreed upon objectives and timelines.

LSEG is a leading global financial markets infrastructure and data provider. Our purpose is driving financial stability, empowering economies and enabling customers to create sustainable growth.

Our purpose is the foundation on which our culture is built. Our values of Integrity, Partnership, Excellence and Change underpin our purpose and set the standard for everything we do, every day. They go to the heart of who we are and guide our decision making and everyday actions.

Working with us means that you will be part of a dynamic organisation of 25,000 people across 65 countries. However, we will value your individuality and enable you to bring your true self to work so you can help enrich our diverse workforce. You will be part of a collaborative and creative culture where we encourage new ideas and are committed to sustainability across our global business. You will experience the critical role we have in helping to re-engineer the financial ecosystem to support and drive sustainable economic growth. Together, we are aiming to achieve this growth by accelerating the just transition to net zero, enabling growth of the green economy and creating inclusive economic opportunity.

LSEG offers a range of tailored benefits and support, including healthcare, retirement planning, paid volunteering days and wellbeing initiatives.

We are proud to be an equal opportunities employer. This means that we do not discriminate on the basis of anyone's race, religion, colour, national origin, gender, sexual orientation, gender identity, gender expression, age, marital status, veteran status, pregnancy or disability, or any other basis protected under applicable law. Conforming with applicable law, we can reasonably accommodate applicants' and employees' religious practices and beliefs, as well as mental health or physical disability needs.

Please take a moment to read this privacy notice carefully, as it describes what personal information London Stock Exchange Group (LSEG) (we) may hold about you, what it's used for, and how it's obtained, your rights and how to contact us as a data subject.

If you are submitting as a Recruitment Agency Partner, it is essential and your responsibility to ensure that candidates applying to LSEG are aware of this privacy notice.