Cato CTRL Threat Research: From Productivity Boost to Ransomware Nightmare - Weaponizing Claude Skills with MedusaLocker
Claude Skills is a new feature from Anthropic that has gained rapid adoption, with more than 17,000+ GitHub stars already since its launch in October 2025, allowing users to create and share custom code modules that expand Claude’s capabilities and streamline workflows. But as this ecosystem grows, Cato CTRL uncovered a serious oversight into how Skills are executed.