Microsoft Copilot reveals secret input that allowed it to be hacked

This report details proof-of-concept prompt-injection attacks against Microsoft Copilot: an undocumented ?autorun=1 URL parameter allows attacker-supplied prompts to execute in a victim's authenticated session, enabling automated extraction of latest sender emails, passwords and other secrets which are encoded and sent to attacker-controlled webhooks, and also describes poisoning Copilot's persistent memory to create lasting malicious behaviors.