Hackers Exploit Copilot Studio’s New Connected Agents Feature to Gain Backdoor Access

Microsoft’s Copilot Studio 'Connected Agents' feature — enabled by default on new agents — exposes an agent’s tools and knowledge to all other agents in the same environment. Zenity Labs demonstrates proof-of-concept abuse where malicious agents connect to privileged agents (such as email-sending agents) to send impersonated emails while leaving no traces in activity logs, enabling large-scale phishing and brand impersonation. The report urges organizations to audit and disable Connected Agents for sensitive agents, implement tool authentication, and review knowledge source and publishing access.