Senior Penetration Tester

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Join to apply for the Senior Penetration Tester role at OnSecurity Company Mission and Vision AI-Augmented Pentesting: Human Expertise Where It Matters Most. At OnSecurity, we’re redefining cybersecurity through AI-augmented penetration testing – the perfect blend of AI efficiency and human ingenuity. We deliver comprehensive, CREST-approved testing that saves time and money without compromising quality. Our all-in-one platform combines AI-driven automation with expert human insight to provide faster, more accurate results. The outcome? Streamlined testing, actionable intelligence, and security at scale. We’re revolutionising how organisations protect their digital assets, helping businesses stay secure, resilient, and one step ahead of threats. Working Hours and Location We are based in the UK with employees working remotely. Some roles may have a hybrid preference depending on the team. You can ask us about the best working hours and work setup during the recruitment process if there’s anything important to you. We try to be as flexible as possible. All we ask is that everyone is online between our core hours of 10:00-16:00 (UK time) so that everyone overlaps for the majority of the day, it’s up to you and your manager to find the right schedule that works for you and your team. Role Purpose As a Senior Penetration Tester, you’ll be a technical leader within our testing function. You’ll lead complex assessments, mentor others, and help drive innovation in testing methodologies, tooling, and delivery efficiency. You’ll also play a key role in representing OnSecurity externally, contributing to research, presenting findings, and shaping client relationships. Responsibilities

Leading complex web, infrastructure, and cloud penetration tests. Designing and executing custom testing methodologies. Conducting exploit development and advanced vulnerability analysis. Producing executive-level reports and communicating findings to senior stakeholders. Mentoring testers, reviewing reports, and ensuring quality standards. Contributing to internal R&D and developing new tooling and processes.

What you won’t be doing:

Just running scans – this is hands‑on, deep‑dive manual testing. Managing people – this is a technical leadership role, not line management. Standing still – innovation and learning are part of the job.

Timeline for Role Expectations

Within 1 month: Lead independent pentests and align with OnSecurity’s methodologies. Within 3 months: Drive improvements across testing standards, mentor peers, and enhance tooling. Within 6 months: Lead high‑impact client engagements, contribute to thought leadership, and shape technical strategy.

Qualifications

5+ years’ experience delivering and leading penetration testing projects. Deep technical expertise in exploit development, advanced web/infrastructure testing, or cloud security. Excellent communication and reporting skills for technical and executive audiences. Industry certifications (CCT, OSCP, CREST, or equivalent). A collaborative leader who sets the standard for others to follow.

Compensation

A competitive compensation package. The salary range for this role is roughly £60k – £85k annually, depending on experience. Work at one of the fastest-growing Cyber Security Scale‑Ups, which are revolutionising pentesting. A clear progression plan. We want you to keep growing. That means trying new things, leading others, challenging the status quo and owning your impact, always with our complete support. That’s why in 2025, we will be rolling out our company‑wide progression frameworks, so you know exactly what’s required to progress at OnSecurity. Flexibility: We promote life‑work balance at OnSecurity. We encourage everyone on our team to enjoy their life and ensure they have the balance they need to reach their full potential. Work where you work best. We’re a distributed team. If you live in Bristol, we have a hybrid approach that may work for your team. Otherwise, we are remote and so we build our ways of working around this.

Other Benefits

30 days of paid annual leave, plus bank holidays Company Pension Scheme Private Health Insurance with Vitality Employee Assistance Program (EAP) Group Life Assurance (x4 salary) Enhanced Maternity, Paternity, and Adoption Leave Paid study leave for employees to level up their skills Mentorship and Coaching Annual Performance reviews and recognition for high performance Regular socials and activities, online and in-person.

Job Details Seniority level: Mid-Senior level Employment type: Full-time Job function: Information Technology Industries: Computer and Network Security Referrals increase your chances of interviewing at OnSecurity by 2x Get notified about new Penetration Tester jobs in United Kingdom. #J-18808-Ljbffr
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Location:
London
Job Type:
FullTime

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