Head of Proactive Security

About Nebius: Nebius is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. The role Nebius is looking for a Head of Proactive Security to establish and lead the Proactive Security pillar. Reporting directly to the CISO, this leader will manage the Red Team, Penetration Testing, Threat Hunting, and Threat Intelligence teams. The role is responsible for anticipating relevant threats, challenging Nebius's defenses, identifying exploitable weaknesses, hunting for adversary activity that may evade existing controls, and converting findings into measurable security improvements. This is a hands-on leadership position for someone who combines offensive-security depth, threat-led thinking, strong operational judgment, and the ability to influence product, engineering, infrastructure, and security stakeholders. Your responsibilities will include: Pillar strategy and leadership Define the Proactive Security strategy, operating model, roadmap, priorities, budget, and success measures in alignment with Nebius's business objectives and threat profile. Build, lead, and develop high-performing Red Team, Penetration Testing, Threat Hunting, and Threat Intelligence teams. Create a unified intelligence-led program in which threat intelligence informs testing and hunting, and findings continuously improve defensive controls. Prioritize work based on crown jewels, material attack paths, emerging threats, major technology changes, incidents, and business risk. <li data-leveltext="" dat