ncat

Use ncat to connect, listen, or interact with a background listener.

SERVERHercules MCP SOURCE0xmihirk/hercules-mcp

High RISK CLASS

Category Execute

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/0xmihirk-hercules-mcp/ncat.md

WHAT IT DOES

What ncat does on Hercules MCP

AI agents invoke ncat to trigger actions in Hercules 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.

RISK

Why ncat is rated High

ncat is a netcat clone commonly used in penetration testing to establish network connections, create reverse shells, and interact with listening services. While it itself does not directly execute code, it is a tool for establishing network communication channels that facilitate command execution and arbitrary interactions with remote systems.

From the tool's definition "ncat to connect, listen, or interact with a background listener" — ncat is a network utility that establishes arbitrary network connections and can send/receive data across sockets, enabling execution of remote commands or data exfiltration.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs ncat safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Hercules MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For ncat, this is the rule to start with:

ncat Rate-limited

ncat 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": {
    "ncat": {
      "limits": [
        {
          "counter": "ncat_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Hercules MCP, apply this rule, and every ncat call is checked against it from then on.

FAQ

Questions about ncat

What does the ncat tool do? +

Use ncat to connect, listen, or interact with a background listener. It is categorised as a Execute tool in the Hercules 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 ncat? +

Register the Hercules MCP server in PolicyLayer and add a rule for ncat: 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 Hercules MCP. Nothing to install.

What risk level is ncat? +

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

Can I rate-limit ncat? +

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

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

ncat is provided by the Hercules MCP server (0xmihirk/hercules-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Hercules, and thousands of servers like it.

This server

All 45 Hercules tools → High-risk tools on this server →

Across the catalogue

All high-risk MCP tools → The MCP Attack Database →

Guides

Govern code and CI agents →Agent sandbox →Least privilege for MCP →