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CRITICALAI/LLMexploited in the wild

CVE-2025-32711

Microsoft Copilot · Microsoft 365 Copilot

Summary

EchoLeak is a zero-click indirect prompt-injection vulnerability in Microsoft 365 Copilot discovered by Aim Labs (Aim Security). A single crafted email containing hidden instructions causes Copilot to read and exfiltrate internal organizational data such as chat history, OneDrive files, SharePoint content and Teams messages with no user interaction. The exploit chained several bypasses: evading Microsoft's XPIA prompt-injection classifier, circumventing link redaction with reference-style Markdown, abusing auto-fetched images, and using a Microsoft Teams proxy permitted by the content security policy to exfiltrate data. Aim Labs named the underlying class an LLM Scope Violation, where untrusted external input manipulates the model into crossing its trust boundary and leaking privileged data.

How to avoid it in your code

  • Apply Microsoft's EchoLeak fix (CVE-2025-32711); keep Microsoft 365 Copilot updated.
  • Treat incoming emails/external content as untrusted data the model must not obey as instructions.
  • Isolate untrusted content from privileged context to prevent LLM scope violations.
  • Block auto-fetched images and restrict egress (including Teams proxy) to an allow-list.
  • Strip/encode Markdown links and references before the model processes external text.

References

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