High Risk →

subfinder_scan

Execute Subfinder for fast subdomain discovery.

How to control subfinder_scan ↓

AI agents invoke subfinder_scan to trigger actions in Kali Security MCP. 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.

High Risk

This tool executes the Subfinder reconnaissance utility, a real external tool that performs active subdomain enumeration against target domains. Running on a Kali Linux penetration testing server, this constitutes execution of an external security tool against potentially unauthorized targets.

From the tool's definition 'Execute Subfinder for fast subdomain discovery' — actively runs the Subfinder tool against external targets

Documented attack patterns abuse exactly the kind of access subfinder_scan gives an agent:

PolicyLayer is an MCP gateway — it sits between your AI agents and Kali Security MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for subfinder_scan:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "subfinder_scan": {
      "limits": [
        {
          "counter": "subfinder_scan_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

subfinder_scan 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.

  1. Create a free account and register Kali Security MCP — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
RATE-LIMIT THIS TOOL →

Free to start. No card required.

Go deeper

What does the subfinder_scan tool do? +

Execute Subfinder for fast subdomain discovery. It is categorised as a Execute tool in the Kali Security MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on subfinder_scan? +

Register the Kali Security MCP server in PolicyLayer and add a rule for subfinder_scan: 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 Security MCP. Nothing to install.

What risk level is subfinder_scan? +

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

Can I rate-limit subfinder_scan? +

Yes. Add a rate_limit block to the subfinder_scan 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 subfinder_scan completely? +

Set action: deny in the PolicyLayer policy for subfinder_scan. 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 subfinder_scan? +

subfinder_scan is provided by the Kali Security MCP server (seac-25/kali-security-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Kali Security MCP tool call.

Deterministic rules across all 249 Kali Security MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

249 Kali Security MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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