Senior Penetration Tester

Hack The Box LTD; Greater London; On-site; GBP 60,000 - GBP 80,000; Full time

Job summary

A leading financial markets infrastructure provider in Greater London seeks a Senior Penetration Tester to join their offensive security team. This hands-on role involves conducting penetration tests across applications and cloud environments. The ideal candidate will possess strong technical skills in various security tools and protocols, with a proven track record in managing security engagements. Constant collaboration and clear communication, combined with technical competency, are essential. This position offers the opportunity to enhance organizational security and contribute to key initiatives.

Qualifications

• Proven hands-on experience in penetration testing of various systems.
• Experience in automating pentesting tasks.
• Ability to write clear, technical reports.

Responsibilities

• Conduct in-depth penetration tests on various environments.
• Compile technical scoping documents and track assessment metadata.
• Document findings clearly and provide remediation guidance.

Skills

Penetration Testing of Web Applications

Use of Burp Suite

Cloud Platforms (AWS, Azure, GCP)

Command-line Tools

Interpersonal Skills in English

Tools

Burp Suite

Docker

Kubernetes

Job description

Overview

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.

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.
• Document engagement details (who, what, when, where) and testing activity logs.
• Define testing team roles, tools, methodologies, schedules, and target systems/environments.
• Identify constraints, exclusions, and limitations affecting engagements.
• Document findings clearly and concisely, providing actionable remediation guidance.
• Collaborate with application teams to scope, perform, and report on security assessments.
• Contribute to team improvements and ensure initiatives and feedback are well documented for future references.
• Contribute to the continuous improvement of testing methodologies, tooling, and automation.
• Stay ahead of emerging threats, vulnerabilities, and offensive security techniques.
• Participate in R&D initiatives as guided by 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.
• 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.

Company Profile

London Stock Exchange Group plc

Website: https://londonstockexchange.com

LSEG is one of the world’s leading providers of financial markets infrastructure and delivers financial data, analytics, news and index products to 44,000+ customers in over 170 countries. We help organisations fund innovation, manage risk and create jobs by partnering with customers at every point in the trade lifecycle: from informing their pre-trade decisions and executing trades to raising capital, clearing and optimisation. Backed by more than three centuries of experience, innovative technologies and a team of over 26,000 people in 65 countries, we are driving financial stability, empowering economies and enabling you to grow sustainably.