Armadin, the AI-native cybersecurity startup founded by Mandiant's Kevin Mandia, has raised $255.5 million in a Series B round that values the company at more than $2.5 billion, the company confirmed Wednesday. The round was co-led by Andreessen Horowitz and Accel, with participation from Bain Capital Ventures, Redpoint, Google Ventures, In-Q-Tel, Kleiner Perkins, Menlo Ventures and existing backers 8VC and Ballistic Ventures.
The raise comes just seven months after Armadin emerged from stealth with $189.9 million in combined seed and Series A funding, at the time the largest such round in cybersecurity history. Armadin has now raised more than $445 million in total.
Mandia, who sold his previous company, Mandiant, to Google for $5.4 billion in 2022, built Armadin around what the company calls an "agentic attacker swarm": fleets of autonomous AI agents that continuously probe a client's networks and applications the way a human red team or a nation-state hacker would, chaining together smaller vulnerabilities into exploitable attack paths. Traditional red-teaming engagements have typically cost companies $20,000 to $30,000 and taken weeks to schedule and run; Armadin's pitch is that its software can simulate a comparable attack in minutes, continuously, at a fraction of the cost.
Betting on automated offense
The round reflects investors' growing appetite for security startups built around autonomous AI agents rather than traditional scanning tools. Mandia has argued that offensive security work — the simulated attacks companies pay for to find their own weaknesses — will become "all-AI in under two years," as large language models have grown more capable at the kind of bug-hunting and exploit-chaining that used to require specialized human expertise.
That same capability is a double-edged sword: security researchers have warned for the past two years that the tools making defense easier to automate are the same ones making it cheaper for attackers to find and exploit flaws at scale. Armadin's investors are, in effect, betting that enterprises will pay a premium to have an AI attacker on their own payroll before someone else's finds the gap first.
Armadin has not disclosed revenue or customer counts, and declined to specify how it will deploy the new capital beyond general references to hiring and product expansion. The jump from a roughly nine-figure valuation in March to more than $2.5 billion in October underscores how quickly investor enthusiasm — and prices — have moved for AI-native security startups this year, a pace that is now drawing comparisons to the early funding cycles around generative AI itself.
