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'.