host_discovery · Kali MCP: Risk & Policy

WHAT IT DOES

What host_discovery does on Kali

AI agents invoke host_discovery to trigger actions in Kali. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why host_discovery needs a policy

This tool executes an nmap ping scan across a network range to enumerate live hosts. It triggers active network reconnaissance against potentially external targets, which can be intrusive, trigger IDS/IPS alerts, and is a common first step in attack chains. The broader server context (penetration testing toolset with Hydra, SQLMap, Metasploit) confirms offensive use potential.

From the tool's definition 'Discover live hosts on a network using nmap ping scan' — actively runs nmap against a target network

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

host_discovery Rate-limited

host_discovery stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "host_discovery": {
      "limits": [
        {
          "counter": "host_discovery_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Kali, so you can run agents against it safely.

FAQ

Questions about host_discovery

What does the host_discovery tool do? +

Discover live hosts on a network using nmap ping scan. It is categorised as a Execute tool in the Kali MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on host_discovery? +

Register the Kali MCP server in PolicyLayer and add a rule for host_discovery: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Kali. Nothing to install.

What risk level is host_discovery? +

host_discovery is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit host_discovery? +

Yes. Add a rate_limit block to the host_discovery rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block host_discovery completely? +

Set action: deny in the PolicyLayer policy for host_discovery. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides host_discovery? +

host_discovery is provided by the Kali MCP server (rangta10/kali-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.