Prompt Injection Defense Weekly

Issue #1: System Prompt Isolation — The One Defense That Blocks Agentic Prompt Injection

This week's attack landscape: TrapDoor weaponizes .cursorrules for AI-config injection, PromptArmor shows Copilot Cowork exfiltrating SharePoint files at 100% success rate. The defense: System Prompt Isolation with a reusable production template you can deploy today.