London Penetration Tester & AI Security Expert

Javelin Group; Greater London; On-site; GBP 70,000 - 110,000; Full time

Benefits offered by this job

25 days holiday

Annual discretionary bonus

Company pension scheme (10% company)

Private medical scheme

Travel insurance

Income protection

Life insurance (5x salary)

Bike2Work scheme

Season ticket loan

Onsite gym

Job summary

Javelin Group in London seeks a Penetration Tester & AI Security Engineer to join the Infrastructure team. You will identify security weaknesses across infrastructure, apps, networks and AI capabilities, and lead remediation efforts.

The role blends traditional testing with secure AI development and client‑facing security reviews. The ideal candidate has hands-on experience across cloud and on‑prem environments, strong AD/Azure/AWS knowledge, and a track record of clear technical reporting.

Qualifications

• Proven experience in penetration testing across infrastructure, web apps, APIs and cloud.
• Strong knowledge of Active Directory, Entra ID, Microsoft 365, Azure and AWS.
• Experience with security tools and REST APIs.
• Understanding of AI security, including prompt-injection testing and red-teaming.
• Scripting in PowerShell or Python; familiarity with Copilot Studio or Azure AI desirable.

Responsibilities

• Conduct penetration testing across infrastructure, applications, networks, AD and cloud environments.
• Identify vulnerabilities, demonstrate impact and work with teams on remediation and retesting.
• Perform authorised security testing of new client platforms and integrations before go‑live.
• Support secure development of in‑house AI solutions, including AI agents and automation.
• Ensure AI solutions comply with security, privacy, access-control and data protection requirements.
• Test AI security controls: prompt-injection, data leakage, excessive permissions, guardrails.
• Conduct AI red-team testing to identify weaknesses in AI apps and agents.
• Review AI identities, API permissions and access to systems like M365, Azure.
• Produce technical findings with practical remediation recommendations.

Skills

Penetration testing

Active Directory

Azure

AWS

AI security

PowerShell

Python

Communication

Tools

Burp Suite

OAuth/OIDC

REST APIs

Copilot Studio

Azure AI

Job description

Javelin Group in London seeks a Penetration Tester & AI Security Engineer to join the Infrastructure team. You will identify security weaknesses across infrastructure, apps, networks and AI capabilities, and lead remediation efforts.

The role blends traditional testing with secure AI development and client‑facing security reviews. The ideal candidate has hands-on experience across cloud and on‑prem environments, strong AD/Azure/AWS knowledge, and a track record of clear technical reporting.