# fin_scan

Perform a FIN scan on the specified target with optional custom arguments.

Agent View of the PolicyLayer registry record for `fin_scan`. HTML page: https://policylayer.com/tools/0xpratikpatil-nmapmcp/fin-scan

## Facts

- Tool: `fin_scan`
- Server: NmapMCP (`0xpratikpatil/nmapmcp`) — https://policylayer.com/tools/0xpratikpatil-nmapmcp.md
- Homepage: https://github.com/0xPratikPatil/NmapMCP
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "fin_scan",
    "arguments": {}
  }
}
```

## Why fin_scan is rated High

A FIN scan sends crafted TCP packets to probe remote systems for open ports while evading firewalls/IDS. This is an active network reconnaissance operation with real external effects (packets sent to targets), making it Execute. It can be used for unauthorized network probing, giving it high severity. It is not Destructive (no data is deleted) but does trigger external operations whose effects depend on arguments.

From the tool's own definition: "'Perform a FIN scan on the specified target' — executes a stealth TCP FIN network scan against external hosts"

## Use case

AI agents invoke fin_scan to trigger actions in NmapMCP. 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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches NmapMCP:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "fin_scan": {
      "limits": [
        {
          "counter": "fin_scan_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on NmapMCP (14)

- `arp_discovery` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/arp-discovery.md
- `disable_dns_resolution` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/disable-dns-resolution.md
- `dns_brute_force` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/dns-brute-force.md
- `idle_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/idle-scan.md
- `no_portscan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/no-portscan.md
- `os_detection` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/os-detection.md
- `ping_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/ping-scan.md
- `portscan_only` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/portscan-only.md
- `scan_top_ports` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/scan-top-ports.md
- `syn_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/syn-scan.md
- `tcp_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/tcp-scan.md
- `udp_scan` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/udp-scan.md
- `version_detection` — Execute — https://policylayer.com/tools/0xpratikpatil-nmapmcp/version-detection.md
- `list_scan` — Read — https://policylayer.com/tools/0xpratikpatil-nmapmcp/list-scan.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=0xpratikpatil-nmapmcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/0xpratikpatil-nmapmcp