Israeli Cyber Firm Rein Security Raises $25 Million for AI Agent Security

Israeli cybersecurity company Rein Security has secured $25 million in Series A funding, bringing its total funding to $35 million. The round was co-led by Glilot Capital and Sienna Venture Capital, with participation from Corner Ventures, Atlacle, and RNP Capital Advisors. Founded in 2024 by Matan Bar Efrat and Natanel Rubin, the company currently employs 31 people and operates offices in Tel Aviv and New York.

The funding comes as organizations rapidly deploy AI agents with increasing access to business systems, data, and workflows, creating new security risks that traditional methods are ill-equipped to handle. Rein Security addresses the dual challenge of securing these AI agents while also defending against sophisticated AI-powered attacks. Their platform utilizes patented sidecar technology that operates at runtime, providing security teams with visibility into every line of code executed by AI agents and every resource they access. It offers full governance and real-time guardrails to block malicious activities.

Rein Security also secures the AI agent supply chain without transmitting company or customer data through gateways or proxies. "Most companies focus on the agents they develop outside the organization; we focus on the agents the organization develops itself," stated co-founder Natanel Rubin in an interview. "We sit in the client's cloud with a completely different technology." He explained that organizations face two main AI-related security problems: those developed independently and those developed by the organization itself. The company is already generating revenue.

Organizations are adopting AI agents faster than they can secure them, with much of the associated risk stemming from automated actions within business systems, often based on instructions from other systems or agents rather than humans. Securing these agents requires understanding and stopping every action they perform, a necessity also driven by rapidly evolving adversarial AI attacks that can overwhelm security teams. This situation demands a shift from vulnerability management to a proactive strategy prioritizing prevention and protection.