Offensive Security Tester in London

The team you’ll be working with:

You can be based ANYWHERE IN THE UK. NTT DATA, a global leader in security services, is seeking a CREST-certified Offensive Security Tester to join its UK Security Practice. This role involves conducting advanced penetration testing engagements, identifying vulnerabilities across diverse IT environments, and providing actionable remediation guidance to enhance client security postures. The ideal candidate will have a strong background in offensive security, a deep understanding of attack techniques, and excellent communication skills to deliver impactful results.

What you’ll be doing:

• Key Responsibilities:

• Conduct comprehensive penetration tests across web applications, network infrastructure, and mobile applications.
• Perform external and internal network penetration testing using industry-standard methodologies.
• Execute wireless security assessments, social engineering engagements, and red team exercises.
• Conduct application security testing, including API and web service assessments.

• Identify, validate, and prioritize security vulnerabilities discovered during testing.
• Analyze attack paths and assess the business impact of identified vulnerabilities.
• Develop proof-of-concept exploits to demonstrate security risks.

• Produce detailed technical reports documenting findings, risks, and remediation recommendations.
• Create executive summaries highlighting business impact and strategic risk concerns.
• Present findings to technical teams and management stakeholders.

• Follow industry-standard penetration testing methodologies (e.g., OWASP, PTES, NIST).
• Maintain and update penetration testing tools and exploitation frameworks.
• Stay current with the latest attack techniques, vulnerabilities, and security research.

• Communicate effectively with clients throughout testing engagements.
• Coordinate testing activities to minimize business disruption.
• Support scoping discussions and provide security awareness briefings to client teams.

What experience you’ll bring:

• Certifications:

• CREST Registered Penetration Tester (CRT) certification required.
• Must meet UK SC Clearance eligibility guidelines.
• Additional certifications preferred (e.g., OSCP, GPEN, CEH).

• Strong technical writing and verbal communication skills.
• Ability to explain complex technical issues to non-technical audiences.
• Excellent time management and attention to detail.

• Bachelor’s degree in computer science, Cybersecurity, or related field.
• Direct experience working in government, military, or intelligence organizations advantageous.
• 3–5 years of experience in penetration testing or offensive security roles.

• Experience conducting red team exercises and adversarial attack simulations.
• Familiarity with threat modeling and risk assessment methodologies.
• Background in information security or IT security operations.

Success Metrics (6–12 Months):

• Complete a minimum of 10 penetration testing engagements per quarter.
• Achieve client satisfaction ratings of 90% or higher for testing services.
• Deliver high-quality technical reports with zero critical errors.
• Stay within defined scope and timelines for all engagements.

Who we are:

We’re a business with a global reach that empowers local teams, and we undertake hugely exciting work that is genuinely changing the world. Our advanced portfolio of consulting, applications, business process, cloud, and infrastructure services will allow you to achieve great things by working with brilliant colleagues, and clients, on exciting projects. Our inclusive work environment prioritises mutual respect, accountability, and continuous learning for all our people. This approach fosters collaboration, well-being, growth, and agility, leading to a more diverse, innovative, and competitive organisation.

We are also proud to share that we have a range of Inclusion Networks such as: the Women’s Business Network, Cultural and Ethnicity Network, LGBTQ+ & Allies Network, Neurodiversity Network and the Parent Network.

We are an equal opportunities employer. We believe in the fair treatment of all our employees and commit to promoting equity and diversity in our employment practices. We are also a proud Disability Confident Committed Employer - we are committed to creating a diverse and inclusive workforce. We actively collaborate with individuals who have disabilities and long-term health conditions which have an effect on their ability to do normal daily activities, ensuring that barriers are eliminated when it comes to employment opportunities. In line with our commitment, we guarantee an interview to applicants who declare to us, during the application process, that they have a disability and meet the minimum requirements for the role. If you require any reasonable adjustments during the recruitment process, please let us know. Join us in building a truly diverse and empowered team.