Senior Security Engineer - Senior Manager at Oaknorth.ai

At OakNorth, we’re on a mission to empower the UK’s most ambitious businesses. Since 2015, we’ve lent over $21 billion across the UK and US, helped create more than 58,000 new homes and 36,000 new jobs, and supported hundreds of thousands of personal savers — all while fuelling the UK economy. Team Mission 🚀  Job Responsibilities: • Plan and execute red team engagements across infrastructure, applications, APIs, and cloud environments using real-world adversary tactics. • Conduct structured threat modelling for new products and platform changes, translating findings into prioritised, trackable security requirements. • Serve as the security architecture expert - reviewing system designs, data flows, and trust boundaries, and defining secure architecture patterns for applications build using cloud-native, containerised, and serverless environments. • Collaborate with engineering teams to define security requirements, review code for vulnerabilities, and ensure security controls are embedded into the development lifecycle. • Develop and execute security testing strategies for AI applications - covering prompt injection, jailbreaking, data poisoning, excessive agency, insecure output handling, and adversarial robustness of LLMs and agentic systems. • Contribute to building a strong security culture through secure coding guidelines, training workshops, and knowledge-sharing across security champions and engineering teams Desired Skills: • 6-7 years in information security with demonstrated depth across red teaming, penetration testing, security architecture, or security engineering. • Proven experience with threat modelling and secure design reviews for customer facing financial systems. • Experience in cloud security (AWS / GCP) including IAM, GuradDuty, WAF, container security, and serverless architectures. • Experience testing AI/ML applications for security vulnerabilities, including prompt injection, data leakage, and adversarial attacks. • Strong understanding of common application security vulnerabilities, including OWASP Top 10, OWASP Top 10 for LLM applications and SANS Top 25. • Excellent written and verbal communication skills, with the ability to clearly articulate risk and influence technical and non-technical stakeholders. • Ability to work independently while collaborating effectively across multiple teams.