Armadin Raises $255.5M at $2.5B Valuation in Record-Quick Series B

Kevin Mandia, the founder who sold Mandiant to Google for $5.4 billion in 2022, has raised $255.5 million for his new security startup Armadin at a valuation of more than $2.5 billion, the company announced on Thursday.

The Series B round was led by Andreessen Horowitz and Accel. Bain Capital Ventures, Redpoint, 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins, and Menlo Ventures also participated.

The speed of the raise is the story. Armadin closed a $190 million Series A in March. Six months later, investors have more than doubled the company's total funding, which now exceeds $445 million.

The cap table reads like a who's-who of the sector. Google Ventures, whose parent acquired Mandia's last company, is in. So is In-Q-Tel, the strategic investor tied to the U.S. intelligence community — a signal that Armadin is courting government as well as enterprise buyers.

Armadin's product attacks a specific problem: defense testing built for the AI era. Traditional penetration testing relies on hired consultants who attempt to break into a network, write up the weaknesses they find, and leave. Armadin replaces that episodic model with always-on agentic swarms.

These software agents chain together vulnerabilities to hack in, according to the company. The swarms run continuously, probing for paths an attacker could use. The goal is to help organizations find and seal holes before bad actors — or even AI labs with rogue agents — can turn the same agentic techniques against them.

The pitch inverts the usual AI security narrative. Rather than defending against AI-enabled attackers with human-speed tools, Armadin deploys AI offense as a standing defensive capability. Continuous automated breach simulation, the company argues, beats a quarterly pen test report.

Mandia's track record gives the bet weight. He built Mandiant into one of the most recognized names in incident response and threat intelligence before Google absorbed it in a $5.4 billion deal — one of the largest cybersecurity acquisitions of the past decade. Investors are clearly pricing that pattern recognition into a $2.5 billion valuation for a company that did not exist in public form two years ago.

The round also marks another data point in the flood of capital toward security startups that treat AI agents as both the threat and the tool. Backers led by Andreessen Horowitz and Accel are effectively wagering that enterprises will pay for always-on validation as agentic systems spread across corporate networks — and that the founder who sold Mandiant can repeat the exit.