refractal - Security Engineer (AI Red Team)
Requirements
• Experience assessing LLM applications, agent workflows or systems that retrieve external content. • Experience building security evaluation suites or testing proposed mitigations systematically. • Experience combining application testing with cloud, identity or infrastructure security assessment. • Radical transparency. We believe the best work happens when everyone feels able to give and receive honest, constructive feedback. • Public service. We see AI security as a form of public service. Getting the AI transition right means putting the right infrastructure in place to manage the threats that come with it, and our work helps protect the institutions and services society depends on. • Fail fast. We test ideas early, seek feedback and learn quickly. We experiment rapidly and change course when something isn't working, without compromising on security. • Pragmatism, not dogmatism. We choose approaches based on how well they solve the problem. That means combining established cybersecurity methods with frontier AI research, questioning our assumptions, and changing our minds when the evidence changes.
Responsibilities
• Design and execute assessments of AI applications and agents, grounded in realistic attacker goals and clearly defined test scope. • Test realistic threats such as indirect prompt injection, misuse of connected tools, sensitive data exposure and attempts to cross permission boundaries. • Build reproducible test cases and small testing tools that demonstrate security impact and distinguish reliable failures from one-off outputs. • Analyse how model behaviour, application design, identity and permissions combine to create vulnerabilities. • Document findings, recommend practical mitigations and retest fixes with the engineers responsible for the affected systems. • SUCCESS IN YOUR FIRST SIX MONTHS • You've established a repeatable assessment approach that connects realistic adversaries, test scenarios and security outcomes. • You've produced actionable findings with reproducible evidence and helped validate the resulting fixes. • You've built a growing set of regression tests that captures recurring failure modes and checks whether fixes hold.
Benefits
• £65K – £125K • Offers Equity • Upload your resume here to autofill key application fields. • Drop your resume here! • Parsing your resume. Autofilling key fields... • or drag and drop here • City and country. • No, I already have the right to work there • Yes, I would need sponsorship • In a sentence or so, why are you interested in joining Refractal? • What did you find, how did you find it, and what was the impact? Links to CVEs, bug bounty reports, write-ups, talks or tools are welcome. • If you haven't done this yet, tell us how you would test an AI agent that can read a user's email and send messages on their behalf. • Within one month • Within three months • In more than three months • Finally, is there anything else you'd like to share? Links to work you're proud of, such as projects, research, writing or a portfolio, are welcome.
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