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 executing 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 rigorous testing and collaboration.
Key Responsibilities
Conduct in-depth penetration tests on applications, infrastructure, and cloud environments.
Take full ownership of assigned pentesting 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
ConstraintSenior Security Specialist – Penetration Testing
s, exclusions, and limitations
Testing activities and event logs
Document findings clearly and concisely, providing actionable remediation guidance.
Collaborate with application teams to scope, execute, 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 current with emerging threats, vulnerabilities, and offensive security techniques.
Participate in R&D initiatives as guided from leadership.
Support knowledge sharing 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.
Strong 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 stakeholders.
Experience working in large, complex enterprise environments.
Fluent communication 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, complex enterprise environments.
Proven track record of successfully managing and executing security engagements for various organizations with differing operational and technical profiles.
Ability to identify, assess, and communicate technical and project risks to stakeholders.
Understanding project requirements and aligning deliverables with agreed upon objectives and timelines.
Career Stage:
Senior AssociateLondon Stock Exchange Group (LSEG) Information:
Join us and be part of a team that values innovation, quality, and continuous improvement. If you're ready to take your career to the next level and make a significant impact, we'd love to hear from you.
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.
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.
You will be part of a collaborative and creative culture where we encourage new ideas. We are committed to sustainability across our global business and we are proud to partner with our customers to help them meet their sustainability objectives. Our charity, the LSEG Foundation provides charitable grants to community groups that help people access economic opportunities and build a secure future with financial independence. Colleagues can get involved through fundraising and volunteering.
LSEG offers a range of tailored benefits and support, including healthcare, retirement planning, paid volunteering days and wellbeing initiatives.
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.
Skills Required
- Hands-on penetration testing of web applications, APIs, thick clients, Active Directory, cloud and cloud-native environments
- Proficiency with Burp Suite and common command-line tools
- Ability to write custom scripts and develop/maintain custom tools/exploits
- Experience automating pentesting tasks
- Strong understanding of application security, network protocols, and operating systems
- Experience with cloud platforms (AWS, Azure, GCP) and containerized environments (Docker, Kubernetes)
- Experience working in large, complex enterprise environments
- Ability to write clear technical reports and communicate findings to technical and non-technical stakeholders
- Fluent English, written and verbal
- Relevant security certifications and engagement with the security community
- Threat modelling experience
- Proven track record managing and executing security engagements and communicating risks
What We Do
LSEG (London Stock Exchange Group) is a diversified international markets infrastructure business —earning our clients’ trust for over 300 years. That legacy of customer-focused excellence ensures that you can rely on our expertise in capital formation, intellectual property and risk and balance sheet management. As global leaders in financial indexing, benchmarking and analytic services, we offer unrivalled access to international capital markets. Our high-performance technology solutions enable companies worldwide to access funds for growth and development. And with our Data & Analytics, Capital Markets and Post Trade divisions, we provide a comprehensive, integrated suite of trusted financial market infrastructure services that help our customers pursue—and achieve—their ambitions. You can count on our open access model for unparalleled partnership, flexibility, stability, and support across all of our businesses. That’s how we make a difference— ensuring people can meet their potential—worldwide.
