đ EchoLeak: The First Zero-Click Attack Against Microsoft 365 Copilot
By Professor Timothy E. Bates, âThe Godfather of Techâ
In the accelerating world of generative AI, EchoLeak stands as a milestone â not for what it adds, but for what it exposes.
It is the first publicly documented zero-click exploit against a widely deployed LLM assistant â Microsoft 365 Copilot â and it delivers a chilling lesson: AI tools donât need to be clicked, opened, or interacted with to become a threat vector.
đ¨ What Is EchoLeak?
EchoLeak allows a remote attacker to steal sensitive organizational data just by sending a specially crafted email. No links need to be clicked. No attachments opened. The only action required? A user interacting with Copilot as usual.
And thatâs what makes it so dangerous.
đ Sources:
đ§ How EchoLeak Works
1. Zero-Click Execution
A malicious email is sent to a user. The user doesnât need to open or click anything. If they use Copilot to summarize or respond to their inbox, the exploit is activated silently.
2. LLM Scope Violation
The attack leverages what researchers call a âscope violationâ â tricking Copilot into interpreting untrusted input (the malicious email) as valid prompt content. This gives the attacker indirect access to:
- Teams messages
- SharePoint files
- OneDrive documents
- Chat histories
- Organizational metadata
3. Bypassing AI Guardrails
EchoLeak evades Microsoftâs content filters using creative workarounds like alternate Markdown formats and open redirects on trusted domains â sneaking past protections like Content Security Policy (CSP).
𧪠Detailed threat analysis: AIM Labs â Microsoft 365 Exploit
đ˘ Whoâs At Risk?
Any organization using Microsoft 365 Copilot.
The exploit existed under default Copilot configurations, meaning most users were vulnerable until Microsoft issued a fix. This includes enterprises, educational institutions, government teams â anyone using AI to assist with documents, chats, emails, and productivity flows.
𧯠Mitigation & Microsoftâs Response
- â Vulnerability Patched: Microsoft has since closed the hole and deployed additional defensive layers.
- đ Data Loss Prevention (DLP): Tag sensitive data and consider restricting Copilotâs access to untrusted external sources.
- âď¸ Copilot Context Settings: Review and reconfigure how much external data is allowed into Copilotâs context.
- đĄď¸ AI-Specific Controls Needed: Existing security tools werenât designed to protect against LLM scope violations. Organizations need AI-native defenses.
đ Why EchoLeak Matters
This is more than a bug fix. EchoLeak is a signal that:
- LLMs are attack surfaces, not just productivity tools.
- AI assistants process untrusted content as context, creating new types of risk.
- Traditional security strategies must evolve to account for AI-specific threat vectors.
EchoLeak didnât break into your system. It asked your AI to hand it the keys â and the AI said yes.
đ§ TGOTâs Final Thoughts:
EchoLeak marks a turning point in the story of enterprise AI. It teaches us that trust boundaries need to be redefined in a world where AI models interact with dynamic, unstructured, and often unverified data.
AI security isnât just about building smarter walls â itâs about teaching your AI what to ignore.
And the time to do that was yesterday.
If your organization is adopting Copilot, ChatGPT Enterprise, or any LLM assistant â get your AI governance playbook in order now.
Because the next exploit wonât ask permission either.
#EchoLeak #Cybersecurity #GenerativeAI #MicrosoftCopilot #AIThreats
