Preventing Zero-Click AI Threats: Insights from EchoLeak
Trend Micro, Tuesday, July 15th, 2025
A zero-click exploit called EchoLeak reveals how AI assistants like Microsoft 365 Copilot can be manipulated to leak sensitive data without user interaction. This entry breaks down how the attack works, why it matters, and what defenses are available to proactively mitigate this emerging AI-native threat.
Key Takeaways
EchoLeak is a zero-click AI vulnerability that exploits Copilot's use of historical contextual data to silently execute hidden prompts without user interaction.
The attack method relies on embedded invisible prompt injection-such as HTML comments or white-on-white text-designed to hijack GenAI interpretation at a later point.
It demonstrates a broader class of risks tied to GenAI features like summarization, RAG (retrieval-augmented generation), and context inheritance.
The incident highlights the importance of securing not just AI models, but also the environments in which they interact with enterprise data, such as emails and SaaS platforms. Without securing these surrounding systems, AI tools can be vectors for critical data exposure and policy violations.
Trend Vision One defends against this class of threats through its AI-powered Email and Collaboration Security, leveraging correlated intelligence detection to transform human intelligence, verify email intentions, analyze user behavior, and correlate suspicious signals.
For GenAI access control, Trend Vision One safeguards the user journey through Zero Trust Secure Access (ZTSA). Its AI Service Access capability inspects the GenAI prompts and responses to prevent potential data leakage and ensure safe usage GenAI prompts and responses to prevent potential data leakage and ensure safe usage.