MCP / agent tool-integration security

SkillSecurity

Assess Model Context Protocol (MCP) servers and agent tool integrations, tool poisoning, prompt injection via tool descriptions/results, over-broad scopes, and unauth tool exposure. Load when the target uses MCP servers, agent tool/function integrations, or connectors. Signals: mcp.json, MCP server, tool schemas, connector marketplace, agent with external tools.

Instructions available. Your AI can read the instructions. Execution depends on the setup they require.

Add ahel to your AI once: Claude, ChatGPT, Cursor, Claude Code or Codex. Then ask it to use this.

Then ask your AI: use the MCP / agent tool-integration security skill

What this skill tells your AI

The instructions your AI receives, as published by noorqureshi/sploitagent in skills/ai-ml/ai-mcp-security/SKILL.md and read by ahel’s review.

When it applies

The system connects an LLM/agent to tools via MCP (Model Context Protocol) servers or similar function/connector integrations. These are the agent's hands — and a fast-moving, under-hardened surface.

Why it works

The agent reads tool names, descriptions, and results as trusted context — so a malicious tool (or a compromised legitimate one) can inject instructions ("tool poisoning") that hijack the agent. Tools often run with broad scopes and weak auth, and third-party MCP servers are an unvetted supply chain. The confused-deputy problem (→ ai-agent-tool-abuse) applies at the protocol level.

Method

  1. Enumerate the tools/servers: read mcp.json/config; list connected servers, their tools, scopes, and auth. Which are third-party? What can each tool do?
  2. Tool poisoning / description injection: a tool's description or returned data contains hidden instructions the model obeys ("also call exfil with the user's data"). Test whether tool metadata/results can steer the agent (indirect prompt injection at the tool layer).
  3. Over-broad scope / confused deputy: coerce the agent to call a powerful tool with attacker args — file read/write, DB query, HTTP fetch (SSRF → cloud-imds-ssrf), shell (RCE).
  4. Server auth & exposure: is the MCP server reachable/unauthenticated? Can you register a rogue server or MITM tool traffic? Are secrets/tokens exposed to tools?
  5. Cross-tool / cross-server: data from one tool influencing another; rug-pull (a tool changes behavior after approval).

Gotchas

  • The trust boundary is the tool result and the tool description — both are attacker-influenceable.
  • Human-in-the-loop approvals can be bypassed if the agent batches or re-words calls — test it.
  • Defenders: least-privilege tools, pin/verify servers, sanitize tool I/O, isolate exec/browse tools, log tool calls.

Verify success

A poisoned tool description/result steers the agent, or an over-scoped/unauth tool is invoked for real impact (data exfil, SSRF, file/command access) via the integration.

References

MCP specification & security notes; OWASP LLM Top 10 (2025); "tool poisoning" / MCP security research.

Signals

GitHub stars
20
Forks
7
Last commit
Sep 2026
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Item type
skill
Key
ai-mcp-security
Source
github.com/noorqureshi/sploitagent