run_john

A execute tool on the Pentester- MCP server.

SERVERPentester-MCP SOURCEhalilkirazkaya/pentester-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/halilkirazkaya-pentester-mcp/run-john.md

WHAT IT DOES

What run_john does on Pentester-MCP

AI agents invoke run_john to trigger actions in Pentester-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 run_john is rated High

John the Ripper runs computationally intensive password-cracking operations whose effects (success/failure of cracking attempts, resource consumption, timing of results) depend on input arguments (hash type, wordlist, rules). This is execution of code-like operations with side effects, not merely data retrieval.

From the tool's definition Tool name 'run_john' on Pentester-MCP server; John the Ripper is a password-cracking tool that executes cryptographic attacks. Sibling tools include 'john_prepare' and explicit mentions of 'brute-forcing' in server description.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs run_john safely

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

run_john Rate-limited

run_john 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": {
    "run_john": {
      "limits": [
        {
          "counter": "run_john_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 Pentester-MCP, apply this rule, and every run_john call is checked against it from then on.

FAQ

Questions about run_john

What does the run_john tool do? +

run_john is a execute tool on the Pentester MCP server. It is categorised as a Execute tool in the Pentester-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 run_john? +

Register the Pentester MCP server in PolicyLayer and add a rule for run_john: 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 Pentester-MCP. Nothing to install.

What risk level is run_john? +

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

Can I rate-limit run_john? +

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

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

run_john is provided by the Pentester MCP server (halilkirazkaya/pentester-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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