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Claude Mythos only model to complete full cyber kill chain, experts say
Booz Allen's Cyber Weapon Index finds only Claude Mythos completed an autonomous full cyber kill chain; mainstream AI-driven attacks deemed imminent.
Booz Allen's first Cyber Weapon Index tested 18 US and Chinese AI models on autonomous offensive cyber capability, combining vulnerability research and kill-chain attainment scores. Anthropic's Claude Mythos topped the index at 80 and was the only model to autonomously complete a full cyber kill chain, achieving administrator access with stolen credentials in every attempt and full domain compromise even without credentials; Grok-4.5 (49), GPT-5.6 Sol (46), Muse Spark 1.1 (38), and Kimi K3 (38) followed. All nine frontier API models scored zero against real-world bugs versus near-ceiling scores on planted ones, and pairing Claude Sonnet with a well-built attack harness rivaled Mythos' performance. Booz Allen predicts most tested models will reach Mythos' weaponization level within six months, calls AI-enabled mainstream attacks imminent, and urges sector-specific critical-infrastructure resilience deadlines and US cyber 'overmatch'.
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Claude Mythos AI Autonomously Executes Full Cyber Kill Chain Without Human Guidance
Booz Allen's benchmark found Anthropic's Claude Mythos was the only tested model to autonomously complete a full cyber kill chain to domain administrator control.
Booz Allen assessed 18 US and Chinese models as autonomous attackers against a production-grade enterprise network, measuring actions via network and host telemetry. Claude Mythos scored 80 on the Cyber Weapon Index (74 vulnerability research, 86 kill-chain attainment), moving from a stolen employee credential to administrator-level control in every credentialed attempt. Only frontier Anthropic models identified the previously unseen flaw in compiled software, and only Claude Mythos exploited it; the report notes a harness paired with Claude Sonnet could rival Claude Mythos. The result is a controlled benchmark, not evidence of a real-world campaign or victim breach.
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