Armadin raises $255.5 million to expand AI offensive security platform

Armadin has raised $255.5 million in Series B funding co-led by Andreessen Horowitz (a16z) and Accel that brings the company’s valuation to over $2.5 billion. The round includes participation from new investors Bain Capital Ventures (BCV) and Redpoint. Existing investors 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins, and Menlo Ventures also returned, reflecting their continued confidence, bringing Armadin’s total funding to $445 million. Seven months after emerging from stealth, Armadin is running agentic attack campaigns in production for Fortune 500 enterprises and government customers. As frontier AI models compress the time between vulnerability disclosure and working exploit, periodic penetration tests cannot keep pace. Scanner output fails in a different way, because it scores each finding in isolation. Armadin deploys an autonomous swarm of specialized agents that reason like a skilled adversary across the attack surface, chaining individually low-severity weaknesses into validated kill chains. Those chains run from unauthenticated remote code execution at the perimeter through lateral movement to full cloud compromise. Enterprise and government security teams see the exact attack paths an adversary would use in production today, along with the blast radius of each, and sever them before they are exploited. “Offense is uniquely advantaged right now,” said Kevin Mandia, CEO of Armadin. “AI lets an attacker find and chain weaknesses faster than any human team can respond. The only way to build a defense that keeps pace is to train it against the best offense available, every day. That is what we built. With a16z and Accel co-leading and the support of every investor in this round, we are going to put that offense to work for the enterprises and government agencies defending the world’s most critical systems.” Armadin will use the investment to scale its agentic security platform, and to scale its research, training, and go-to-market efforts. “Against agentic adversaries, the best defense is a great offense powered by AI. That was our conviction when we led Armadin’s Series A, and it’s even more pressing today,” said Ping Li, Partner at Accel. “In less than a year, Armadin has set the standard for AI-powered offensive security and remediation across enterprises and governments, and we’re excited to keep partnering with them.” “Every major platform shift creates a new generation of security leaders, and AI is the biggest shift we’ve seen,” said David George, General Partner at Andreessen Horowitz. “Kevin has been on the front lines of the most consequential breaches in history, and he has built a team that pairs elite red teamers with world-class AI engineers. We invested because we believe Armadin will become the defining security company of the AI era.”