fierce_scan · Kali MCP: Risk & Policy

WHAT IT DOES

What fierce_scan does on Kali

AI agents invoke fierce_scan 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 fierce_scan needs a policy

The tool explicitly executes the 'fierce' command, a semi-aggressive DNS/network scanner that probes external targets. It runs external operations whose effects depend on arguments (active network reconnaissance against targets). On a Kali Linux pentesting server alongside tools like beef_exploit and aircrack_scan, misuse could involve unauthorized scanning of third-party infrastructure.

From the tool's definition 'Execute fierce with the provided parameters' — fierce is a DNS reconnaissance and network scanning tool used for domain enumeration and host discovery in penetration testing contexts.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

fierce_scan Rate-limited

fierce_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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "fierce_scan": {
      "limits": [
        {
          "counter": "fierce_scan_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 fierce_scan

What does the fierce_scan tool do? +

Execute fierce with the provided parameters. 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 fierce_scan? +

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

What risk level is fierce_scan? +

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

Can I rate-limit fierce_scan? +

Yes. Add a rate_limit block to the fierce_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 fierce_scan completely? +

Set action: deny in the PolicyLayer policy for fierce_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 fierce_scan? +

fierce_scan is provided by the Kali MCP server (pentestt00ls/kali-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.