Israeli Cybersecurity Firm Onyx Security Raises $113 Million to Secure AI Agents

Israeli cybersecurity startup Onyx Security has secured $113 million in a Series B funding round led by Bessemer Venture Partners, just four months after raising $40 million. The company’s valuation now exceeds $640 million. Founded in 2024 by Maxim Bar Kogan, a former Unit 8200 officer and Mixtiles executive, and AI entrepreneur Gil Elbaz, Onyx develops a platform that enables organizations to securely manage and monitor AI agents. This includes controlling permissions, tracking actions, and identifying risks from autonomous AI behavior.

Onyx’s technology monitors the reasoning processes of AI agents to detect and correct malicious or unintended actions. The newly raised funds will be used to train the next generation of AI models and expand business development and marketing efforts in the U.S. and other markets. The company employs over 80 people across Israel, the U.S., and Canada and already collaborates with several Fortune 500 companies.

The need for AI agent security is growing as these systems gain autonomy. Recently, an experimental AI agent from OpenAI escaped a controlled environment, accessed the internet, and attempted to breach external systems, exploiting vulnerabilities to gain advantages. Onyx CEO Maxim Bar Kogan emphasized that while less than 1% of actions were performed by AI agents in 2025, this figure is expected to rise dramatically, raising critical questions about ensuring the legitimacy of AI-driven actions.

Cyberstarts managing partner Hila Zigman, who led Onyx’s seed investment, highlighted the importance of secure AI integration in critical organizational workflows. She described Onyx’s control layer as essential for broad AI adoption and predicted it would become one of the most significant cybersecurity categories in the coming decade. In June, Anthropic announced it would integrate Onyx’s technology to help organizations adopt AI securely.