“EchoLeak” Zero-Click Hack Exposes Microsoft 365 Copilot’s Silent Data Leak Risk

Identified by Aim Security, the flaw allows a hacker to send a single crafted email that Copilot processes silently—no user clicks required. 


A serious cybersecurity flaw named EchoLeak has been discovered in Microsoft 365 Copilot, marking the first-known zero-click attack targeting an AI assistant. Identified by Aim Security, this vulnerability allows hackers to exploit Microsoft's AI-powered tool without any user interaction — no clicks, no downloads, and no visible prompts.

With zero-click attacks, malicious actors bypass traditional defenses by embedding hidden prompts in a single crafted email. Once received, Microsoft 365 Copilot silently processes the email, automatically accessing internal files, scanning sensitive information, and transmitting it externally — all without alerting the user or triggering standard security protocols.

What makes EchoLeak particularly alarming is its stealth: corporate data is exfiltrated without the user even knowing an attack has occurred. The exploit completely bypasses Microsoft's built-in data loss prevention and email security filters, raising significant concerns about the security of AI tools integrated into enterprise software.

This attack underscores the growing risk of AI integration in workplace systems. As AI assistants like Microsoft 365 Copilot become more deeply embedded in email, documentation, and collaboration platforms, they also become attractive targets for sophisticated cybercriminals.

Security experts are now urging organizations to reassess how they deploy AI tools in their environments and to demand greater transparency and cybersecurity accountability from tech providers. Enhanced AI safety protocols, robust prompt injection prevention, and multi-layered access controls are being recommended to avoid future breaches.

The EchoLeak vulnerability is a wake-up call for the tech industry, emphasizing that while AI can enhance productivity, it also introduces new cybersecurity attack surfaces that must be addressed urgently. Microsoft has yet to release an official patch or comment on the timeline for fixing the issue.

Also Read: Microsoft to include Copilot in Microsoft 365 for consumers