ARMADIN , the AI-native offensive security startup founded by Mandiant’s Kevin Mandia, has raised $255.5 million in a Series B round at a valuation exceeding $2.5 billion. The funding brings Armadin’s total raise to about $445 million, just seven months after the company publicly launched. Andreessen Horowitz and existing backer Accel co-led the round, with new investments from Bain Capital Ventures and Redpoint.
The financing will be used to expand Armadin’s agentic security platform and scale its research, model training and go‑to‑market operations, according to the firm.
The company describes its approach as deploying swarms of AI agents that emulate skilled adversaries to map and test an organisation’s attack surface. In August, Armadin and TENEX[.]ai carried out a live AI cyberattack exercise, Behavioural tests involved 1,300 attacks across 26,000 agents, with about 17 million offensive actions against more than 25,000 services. The exercise produced 238 security findings, including 98 deemed significant, which were chained into 38 validated attack paths.
Armadin states that all actions passed through a safety layer controlled by a guardrail and human feedback, with no privileged credentials or source code access used in the tests. The company’s leadership includes Mandia as CEO, with CTO Travis Lanham, Chief Offensive Security Officer Evan Peña, and Chief Architect David Slater. Existing backers include 8VC, Ballistic Ventures, GV, In‑Q‑Tel, Kleiner Perkins and Menlo Ventures.