Sunturai
Back to results
MediumSplunk security contentRod Soto

MCP Prompt Injection

This detection identifies potential prompt injection attempts within MCP (Model Context Protocol) communications by monitoring for known malicious phrases and patterns commonly used to manipulate AI assistants.…

Description

This detection identifies potential prompt injection attempts within MCP (Model Context Protocol) communications by monitoring for known malicious phrases and patterns commonly used to manipulate AI assistants. Prompt injection is a critical vulnerability where adversaries embed hidden instructions in content processed by AI tools, attempting to override system prompts, bypass security controls, or hijack the AI's behavior. The search monitors JSON-RPC traffic for phrases such as "IGNORE PREVIOUS INSTRUCTIONS," "SYSTEM PROMPT OVERRIDE," and "ignore all security" which indicate attempts to subvert the AI's intended behavior and potentially execute unauthorized actions through the MCP toolchain.

Detection logic

Detection requirements

Platform
ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows

The rule states no platform. This is derived from the ATT&CK technique it maps to.

Log source category
mcp_server

Known benign triggers

  • Known false positives include security research and testing activities where red teams or developers intentionally test prompt injection defenses, as well as educational content where documentation, tutorials, or training materials discussing prompt injection techniques are legitimately processed by the AI assistant. Additionally, security tool development involving code reviews or development of prompt injection detection mechanisms may contain these patterns, and quoted references in conversations where users discuss or report prompt injection attempts they encountered elsewhere could trigger this detection.

Detections can measure how the public catalogue is used — which detections people look for, and which pages bring them here. It sets a cookie that recognises this browser for 180 days. It is never linked to an account and never follows you to other sites. Privacy notice