Principal Penetration Tester

Role Overview

• Lead and deliver advanced penetration testing across web applications, RESTful APIs, backend services, mobile connected services and supporting application platforms.
• Assess Java based backend systems, especially Spring Boot services, microservice architectures, API gateways and Backend for Frontend layers.
• Test authentication, authorisation, orchestration, input validation, session handling, token management and data exposure risks across modern digital journeys.
• Carry out security testing across cloud hosted and containerised application environments, ideally on AWS, where platform or configuration weaknesses affect application risk.
• Review outputs from SAST, DAST and related controls, separate noise from genuine risk, and help development teams understand what matters and what should be fixed first.
• Support threat modelling and design review activity by translating design and architecture decisions into sensible testing scope and coverage.
• Support release and project assurance by providing clear views on testing depth, remediation expectations and risk based sign off inputs.
• Help develop practical application security testing standards, playbooks and ways of working that can be applied across BAU and project delivery.
• Develop and mature an internal purple team methodology that can be used alongside security testing activity and external red team exercises.
• Support offensive security planning with Security Testing leadership and Cyber Defence so that simulations and adversary led assessments are tied to the maturity of defensive controls and operational priorities.
• Use strong Linux and Windows knowledge to identify realistic exploitation paths across hosts, applications and supporting services.
• Bring practical knowledge of binary exploitation and lower level technical analysis where it adds value to application, platform or software component assessments.
• Apply ATT&CK aligned thinking when shaping offensive scenarios, attack paths and purple team test cases.
• Use knowledge of exploit chaining, post exploitation tradecraft, EDR and AV evasion concepts, and other offensive security techniques where they improve the realism and value of testing.
• Contribute to selected specialist work, including hardware focused testing or low level technical analysis, where there is a clear business need and the activity supports the wider security testing plan.
• Work with external offensive security partners and turn outputs into practical lessons, follow up actions and measurable improvements.
• Act as a senior technical point of reference within the Security Testing function.
• Coach others in the team and help raise the standard of testing, reporting and technical analysis.
• Improve internal methods, test approaches and reporting so that the function becomes more consistent and easier to scale.

Requirements

• Strong hands on experience in application penetration testing across web applications, APIs and service based architectures.
• Strong understanding of Java based backend systems, especially Spring Boot, RESTful APIs and microservice patterns.
• Experience testing API gateways and Backend for Frontend layers, including authentication, authorisation, orchestration and data validation.
• Practical knowledge of cloud hosted applications, ideally on AWS, including containerised services and common platform security controls.
• Good understanding of modern web and mobile application patterns, enough to assess API consumption, session handling, trust boundaries and data exposure risk.
• Strong practical knowledge of Linux and Windows operating systems, including privilege escalation paths, host weaknesses, credential handling risks and exploitation approaches relevant to application environments.
• Working knowledge of binary exploitation and lower level vulnerability analysis where relevant to application, runtime or platform risk.
• Ability to carry out manual testing beyond automated tooling, including business logic weakness, exploit chaining and cross layer issues.
• Ability to explain findings clearly to both technical and non technical stakeholders and provide practical remediation advice.
• Experience shaping testing approach, methodology or standards rather than only delivering assessments.
• Experience with mobile application assessment.
• Experience with secure code review or code assisted testing.
• Experience with ATT&CK informed assessments, adversary emulation support or purple team exercises.
• Familiarity with EDR and AV evasion concepts, exploit development, vulnerability research or offensive tooling beyond standard application testing.
• Exposure to hardware, embedded or other specialist low level testing techniques.
• Experience in regulated, high availability or transaction critical environments.
• Relevant certifications such as CREST, OSCP, OSWE, OSEP or equivalent demonstrable experience.
• Experience with WAF technology and implementation.

Tech Stack

• AWS
• Cloud
• Java
• Linux
• Spring
• Spring Boot
• SpringBoot

Benefits

• Company Bonus Scheme
• Matched pension contributions up to 8.5%
• 26 days annual leave + 2 Life Days (and bank holidays)
• Single Private Health Cover
• Complimentary Private Medical
• Income Protection
• Flexible Benefits – EV Scheme, Money Coach, Will Writing, Mortgage Advice, Dental and Eye Care Schemes.
• Enhanced Family Leave (Maternity, Paternity, Adoption)
• Wellness Allowance £500
• Employee Assistance Programme
• Discounted Health Assessments
• Volunteering Days
• Matched Funding