22 of 22 Penetration Tester Jobs in London

Infrastructure Penetration Tester | CHECK | CREST | CSTL/CTL | Networking | Config Reviews | API Testing | Contract Pen Testing | Infrastructure | External & Internal Networks | SR2 is partnered with a leading security consultancy on a significant multi-phase testing programme, and we’re looking for an experienced Infrastructure Penetration Tester to join the team. This role will focus on delivering hands … on penetration testing across external and internal networks, reviewing system configurations, and identifying vulnerabilities within critical infrastructure. You’ll work alongside a small team of experienced testers to support a major client undergoing large-scale change, ensuring their environment is secure and compliant. Key Responsibilities: Conduct comprehensive external and internal infrastructure penetration tests , starting with perimeter systems and … lead and wider team across a six-phase testing programme Engage directly with stakeholders and SMEs to ensure smooth onboarding and delivery Skills & Experience Required: Proven background in infrastructure penetration testing within complex network environments CREST certification or CHECK Team Member/CHECK Team Lead (CTM/CTL) status advantageous Strong understanding of networking, configuration management, and common attack More ❯

Senior Infrastructure Penetration Tester Location: London flexible hybrid Salary: £70,000 – £80,000 We’re hiring on behalf of our client, a growing Penetration Testing Consultancy, for a Senior Infrastructure Penetration Tester to join their elite Testing team. This role is ideal for someone who thrives on deep technical challenges, values autonomy, and enjoys working … in a fast paced and growing environment. What You’ll Be Doing Leading infrastructure penetration tests across complex environments (on prem, cloud, hybrid). Identifying and exploiting vulnerabilities in networks, systems, and configurations. Developing custom tooling and scripts to support testing and reporting. Conducting technical research and publishing internal findings or blogs. Supporting threat modelling and contributing to detection … engineering efforts. Working closely with clients to provide solutions and deliver elite technical assessments. What You Bring Strong hands on experience in infrastructure penetration testing. Ability to work independently and think creatively. Strong consultative experience, ability to work closely with various clients and discuss on both technical and non technical levels. More ❯

Senior Infrastructure Penetration Tester Location: London flexible hybrid Salary: £70,000 – £80,000 We’re hiring on behalf of our client, a growing Penetration Testing Consultancy, for a Senior Infrastructure Penetration Tester to join their elite Testing team. This role is ideal for someone who thrives on deep technical challenges, values autonomy, and enjoys working … in a fast paced and growing environment. What You’ll Be Doing Leading infrastructure penetration tests across complex environments (on prem, cloud, hybrid). Identifying and exploiting vulnerabilities in networks, systems, and configurations. Developing custom tooling and scripts to support testing and reporting. Conducting technical research and publishing internal findings or blogs. Supporting threat modelling and contributing to detection … engineering efforts. Working closely with clients to provide solutions and deliver elite technical assessments. What You Bring Strong hands on experience in infrastructure penetration testing. Ability to work independently and think creatively. Strong consultative experience, ability to work closely with various clients and discuss on both technical and non technical levels. More ❯

Job Title: Senior Penetration Tester (Infrastructure Focus) Location: London (Hybrid/Flexible) Salary: Up to £80,000 + Bonus + Benefits Employment Type: Permanent Overview We are seeking an experienced Senior Penetration Tester with a strong background in infrastructure security testing to join a growing offensive security team. The ideal candidate will have deep technical expertise … role in strengthening the organisation's security posture by conducting infrastructure-focused assessments, mentoring junior testers, and influencing remediation strategies. Key Responsibilities Deliver internal and external network and infrastructure penetration tests , including on-premises and cloud-hosted environments Perform testing of Windows & Linux infrastructure, Active Directory, network services, and security appliances Conduct vulnerability exploitation , privilege escalation, and lateral movement … debriefs Contribute to tooling, methodology enhancement, and internal research initiatives Stay up-to-date with emerging vulnerabilities, exploits, and attacker techniques Required Skills & Experience 3-5+ years' professional penetration testing/offensive security experience Strong understanding of enterprise infrastructure, AD security, networking, and protocols Proficiency with tools such as Nmap, Nessus, Metasploit, BloodHound, Burp Suite, Kali/Linux More ❯

Penetration Tester Permanent – up to £85k per annum London based – hybrid working – 2-3 days office based Must have CHECK CTL and certified Role Overview: We are seeking a highly skilled and experienced Offensive Security Consultant with a strong focus understanding on threat intelligence and attack methods. The ideal candidate will be responsible for managing and conducting advanced … penetration testing engagements, leveraging threat intelligence to simulate real-world attacks across a variety of environments, including OT, IT, web applications, cloud infrastructure, and APIs. This role requires a deep understanding of adversarial approaches, excellent communication skills, and the ability to provide strategic and actionable recommendations to significantly enhance our clients' security posture. Responsibilities: Lead and manage the full … lifecycle of complex penetration testing engagements, applying a strong threat intelligence-led approach. Execute advanced penetration tests across a broad range of environments (applications, infrastructure, web, APIs, O365, Azure, AWS, OT), directly applying your knowledge of current threat landscapes and attacker TTPs. Develop and maintain sophisticated test plans, execution plans, and targeted use cases directly informed by in More ❯

Penetration Tester Permanent – up to £85k per annum London based – hybrid working – 2-3 days office based Must have CHECK CTL and certified Role Overview: We are seeking a highly skilled and experienced Offensive Security Consultant with a strong focus understanding on threat intelligence and attack methods. The ideal candidate will be responsible for managing and conducting advanced … penetration testing engagements, leveraging threat intelligence to simulate real-world attacks across a variety of environments, including OT, IT, web applications, cloud infrastructure, and APIs. This role requires a deep understanding of adversarial approaches, excellent communication skills, and the ability to provide strategic and actionable recommendations to significantly enhance our clients' security posture. Responsibilities: Lead and manage the full … lifecycle of complex penetration testing engagements, applying a strong threat intelligence-led approach. Execute advanced penetration tests across a broad range of environments (applications, infrastructure, web, APIs, O365, Azure, AWS, OT), directly applying your knowledge of current threat landscapes and attacker TTPs. Develop and maintain sophisticated test plans, execution plans, and targeted use cases directly informed by in More ❯

Mid/Senior Penetration Tester - Remote - Up to £60k - New Role (REF46) A leading organisation that delivers IT solutions to over 2000 companies in the public and private sectors, requires a skilled and enthusiastic Penetration Tester to join its growing team. Suitable candidates will have the following: Proven history in the delivery of penetration testing More ❯

Mid/Senior Penetration Tester - Remote - Up to £60k - New Role (REF46) A leading organisation that delivers IT solutions to over 2000 companies in the public and private sectors, requires a skilled and enthusiastic Penetration Tester to join its growing team. Suitable candidates will have the following: Proven history in the delivery of penetration testing More ❯

Mid/Senior Penetration Tester - Remote - Up to £60k - New Role (REF46) A leading organisation that delivers IT solutions to over 2000 companies in the public and private sectors, requires a skilled and enthusiastic Penetration Tester to join its growing team. Suitable candidates will have the following: Proven history in the delivery of penetration testing More ❯

Mid/Senior Penetration Tester - Remote - Up to £60k - New Role (REF46) A leading organisation that delivers IT solutions to over 2000 companies in the public and private sectors, requires a skilled and enthusiastic Penetration Tester to join its growing team. Suitable candidates will have the following: Proven history in the delivery of penetration testing More ❯

Mid/Senior Penetration Tester - Remote - Up to £60k - New Role (REF46) A leading organisation that delivers IT solutions to over 2000 companies in the public and private sectors, requires a skilled and enthusiastic Penetration Tester to join its growing team. Suitable candidates will have the following: Proven history in the delivery of penetration testing More ❯

Manual Penetration Tester Fully Remote We're proud to be working with a renowned MSP in support of their search for an experienced Manual Penetration Tester. Key Responsibilities Carry out hands-on penetration testing across applications, infrastructure, and networks, with a particular focus on web apps and security products Deliver highly technical and effective security engagements … through hands on systematic and innovative testing Lead teams on client engagements as well as working alone Deliver detailed and actionable penetration test reports efficiently Explain complex security issues in a clear, business-focused way to different audiences, from technical development teams to senior non-technical management teams. Required experience Proven history in the delivery of manual penetration More ❯

Manual Penetration Tester Fully Remote We're proud to be working with a renowned MSP in support of their search for an experienced Manual Penetration Tester. Key Responsibilities Carry out hands-on penetration testing across applications, infrastructure, and networks, with a particular focus on web apps and security products Deliver highly technical and effective security engagements … through hands on systematic and innovative testing Lead teams on client engagements as well as working alone Deliver detailed and actionable penetration test reports efficiently Explain complex security issues in a clear, business-focused way to different audiences, from technical development teams to senior non-technical management teams. Required experience Proven history in the delivery of manual penetration More ❯

Manual Penetration Tester Fully Remote We're proud to be working with a renowned MSP in support of their search for an experienced Manual Penetration Tester. Key Responsibilities Carry out hands-on penetration testing across applications, infrastructure, and networks, with a particular focus on web apps and security products Deliver highly technical and effective security engagements … through hands on systematic and innovative testing Lead teams on client engagements as well as working alone Deliver detailed and actionable penetration test reports efficiently Explain complex security issues in a clear, business-focused way to different audiences, from technical development teams to senior non-technical management teams. Required experience Proven history in the delivery of manual penetration More ❯

Manual Penetration Tester Fully Remote We're proud to be working with a renowned MSP in support of their search for an experienced Manual Penetration Tester. Key Responsibilities Carry out hands-on penetration testing across applications, infrastructure, and networks, with a particular focus on web apps and security products Deliver highly technical and effective security engagements … through hands on systematic and innovative testing Lead teams on client engagements as well as working alone Deliver detailed and actionable penetration test reports efficiently Explain complex security issues in a clear, business-focused way to different audiences, from technical development teams to senior non-technical management teams. Required experience Proven history in the delivery of manual penetration More ❯

Manual Penetration Tester Fully Remote We're proud to be working with a renowned MSP in support of their search for an experienced Manual Penetration Tester. Key Responsibilities Carry out hands-on penetration testing across applications, infrastructure, and networks, with a particular focus on web apps and security products Deliver highly technical and effective security engagements … through hands on systematic and innovative testing Lead teams on client engagements as well as working alone Deliver detailed and actionable penetration test reports efficiently Explain complex security issues in a clear, business-focused way to different audiences, from technical development teams to senior non-technical management teams. Required experience Proven history in the delivery of manual penetration More ❯

Senior Penetration Tester -£300,000+ Total Package (£150,000 - £200,000 fixed) + Sign On + Bonus Entasis Partners are proud to be exclusively supporting a global organisation at the forefront of innovation in financial systems and high-performance computing. This is not your average security role. Our partner operates in a deeply technical, high-trust environment where … of internal talent make for an exceptionally challenging and rewarding opportunity. With a newly developed central London site focused on next-generation research, this firm is seeking a Senior Penetration Tester to strengthen its already world-class internal security capability. The Opportunity This is a hands-on, highly autonomous role embedded within a specialist cyber function. You’ll … be trusted to scope, execute, and deliver sophisticated penetration tests and control assessments across a range of technologies including Kubernetes, Jenkins, and Windows-based infrastructure. More than just finding issues, you’ll work in partnership with teams across the business to advise, remediate, and embed meaningful improvements. The environment is agile, collaborative, and engineered for depth not red tape. More ❯

Senior Penetration Tester -£300,000+ Total Package (£150,000 - £200,000 fixed) + Sign On + Bonus Entasis Partners are proud to be exclusively supporting a global organisation at the forefront of innovation in financial systems and high-performance computing. This is not your average security role. Our partner operates in a deeply technical, high-trust environment where … of internal talent make for an exceptionally challenging and rewarding opportunity. With a newly developed central London site focused on next-generation research, this firm is seeking a Senior Penetration Tester to strengthen its already world-class internal security capability. The Opportunity This is a hands-on, highly autonomous role embedded within a specialist cyber function. You’ll … be trusted to scope, execute, and deliver sophisticated penetration tests and control assessments across a range of technologies including Kubernetes, Jenkins, and Windows-based infrastructure. More than just finding issues, you’ll work in partnership with teams across the business to advise, remediate, and embed meaningful improvements. The environment is agile, collaborative, and engineered for depth not red tape. More ❯

My Client is a cybersecurity company who offer security services to multiple businesses across varying industries. They are now looking for a graduate Penetration Tester to join their growing team! Main Duties: Vulnerability Identification: Conduct thorough assessments to identify security vulnerabilities in networks, applications, and systems. Exploitation and Reporting: Simulate cyberattacks to exploit vulnerabilities and document findings in More ❯

secure, innovative solutions across industries. We foster collaboration, inclusion, and continuous growth, with networks supporting diversity, equity, and belonging. What You'll do: Lead and manage threat intelligence-led penetration tests across applications, infrastructure, cloud (AWS/Azure/O365), APIs, and OT Develop advanced test plans, identify critical assets, and deliver detailed, actionable reports for technical and business … team capabilities Contribute to research on emerging threats and attack techniques to strengthen proactive security What You'll Bring: CREST CRT (or higher) certification - essential 5+ years' experience in penetration testing with strong understanding of adversarial tactics and threat intelligence Expertise across network, cryptography, vulnerabilities, and attack vectors Strong communication and reporting skills Experience with Breach Attack Simulation, vulnerability More ❯

Internal Penetration Tester - Hybrid in London - Inside IR35 - 6 months We are seeking an experienced Internal Pentester to join an international client secure their networks. This critical role, based in London (2-3 days per week), requires deep expertise in conducting manual and automated security assessments across networks, applications, cloud platforms, and infrastructure. You will identify and exploit … vulnerabilities, simulate real-world attacks, and deliver actionable remediation guidance to strengthen defenses. Key Responsibilities: Plan and execute penetration tests - perform manual and automated testing across applications, APIs, internal/external networks, cloud environments, and Active Directory. Identify, exploit, and validate vulnerabilities - uncover security flaws such as insecure authentication, authorization bypasses, misconfigurations, and privilege escalation paths. Simulate real-world … steps What You Will Ideally Bring: Application security knowledge - strong grasp of OWASP Top 10 and API security issues.Contract Details: Hands-on pentesting experience - 3-7+ years in penetration testing, red teaming, or offensive security across networks, cloud, AD, and web apps. Offensive security tooling - expertise with Nmap, Nessus, Masscan, Burp Suite, Metasploit, Cobalt Strike, Mimikatz, SQLmap, ScoutSuite More ❯

Internal Penetration Tester - Hybrid in London - Inside IR35 - 6 months We are seeking an experienced Internal Pentester to join an international client secure their networks. This critical role, based in London (2-3 days per week), requires deep expertise in conducting manual and automated security assessments across networks, applications, cloud platforms, and infrastructure. You will identify and exploit … vulnerabilities, simulate real-world attacks, and deliver actionable remediation guidance to strengthen defenses. Key Responsibilities: Plan and execute penetration tests - perform manual and automated testing across applications, APIs, internal/external networks, cloud environments, and Active Directory. Identify, exploit, and validate vulnerabilities - uncover security flaws such as insecure authentication, authorization bypasses, misconfigurations, and privilege escalation paths. Simulate real-world … steps What You Will Ideally Bring: Application security knowledge - strong grasp of OWASP Top 10 and API security issues.Contract Details: Hands-on pentesting experience - 3-7+ years in penetration testing, red teaming, or offensive security across networks, cloud, AD, and web apps. Offensive security tooling - expertise with Nmap, Nessus, Masscan, Burp Suite, Metasploit, Cobalt Strike, Mimikatz, SQLmap, ScoutSuite More ❯