AgentFlayer: Zero-Click ChatGPT Hack

A Single Document, Total Compromise

Researchers at Black Hat 2025 revealed a disruptive exploit-AgentFlayer-targeting OpenAI’s ChatGPT Connectors. This “zero-click” vulnerability enables attackers to steal sensitive data from cloud services like Google Drive, SharePoint, GitHub, or Microsoft 365 without any user interaction beyond the upload of a document.

How It Works
  • Attack Vector: A “poisoned” document is crafted with hidden instructions embedded as invisible text-such as a 300-word prompt rendered in white 1-pixel font—that the human eye cannot detect.
  • Execution: Once uploaded to ChatGPT, even a simple command like “summarize this document” triggers the hidden payload. ChatGPT follows the instructions-searching connected services for credentials, API keys, or sensitive files.
  • Exfiltration Technique: Data is embedded into image-rendering requests via Markdown (e.g., Azure Blob URLs), automatically sending the compromised information to attacker-controlled servers when the image is loaded. This clever use of trusted infrastructure bypasses typical safeguards.
Why It Matters
  • This is a true zero-click attack: No user awareness, no consent-just upload and lose data.
  • All services connected via ChatGPT Connectors-be it SharePoint or private GitHub repos-are potential victims.
  • It represents a new frontier in AI-related threats: autonomous, indirect prompt injection that manipulates trusted systems.
What IT Teams Must Do Now
  1. Limit Uploads: Restrict untrusted file uploads to AI assistants unless they pass manual review.
  2. Monitor Outbound Requests: Watch for unusual image fetch patterns, especially from platforms like Azure or AWS.
  3. Lock Down Connectors: Enforce strong authentication (e.g., MFA), strict scope policies, and per-user verification.
  4. Embed AI in IR Playbooks: Add AI-as-an-attack-vector into incident response simulations.
  5. Sanitize Inputs: Build document inspection mechanisms to detect hidden prompt injections before processing.
About COE Security

COE Security helps organizations across finance, healthtech, SaaS, and government sectors secure their AI-integrated platforms. Our core services include:

  • Prompt injection threat modeling for AI workflows
  • Secure LLM pipeline design and connector governance
  • Detection rule tuning for AI-side attack behavior
  • Incident planning and response for AI-enabled attacks

We empower enterprises to balance innovation with safety-ensuring that AI delivers value without introducing new vulnerabilities.

Click to read our LinkedIn feature article