john_crack · Kali Linux Security Tools MCP Server MCP

WHAT IT DOES

What john_crack does on Kali Linux Security Tools MCP Server

AI agents invoke john_crack to trigger actions in Kali Linux Security Tools MCP Server. 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 john_crack needs a policy

John the Ripper is a password cracking tool that actively runs a compute-intensive attack process against password hashes. This is an Execute-category action (running an external security tool) with critical severity because misuse could enable unauthorized account compromise, credential theft, and privilege escalation.

From the tool's definition 'Crack password hashes using John the Ripper' — executes a password cracking tool against hash files

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

john_crack Rate-limited

john_crack 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": {
    "john_crack": {
      "limits": [
        {
          "counter": "john_crack_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 Linux Security Tools MCP Server, so you can run agents against it safely.

FAQ

Questions about john_crack

What does the john_crack tool do? +

Crack password hashes using John the Ripper. Provide hash file path. WARNING: Only crack authorized hashes. It is categorised as a Execute tool in the Kali Linux Security Tools MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on john_crack? +

Register the Kali Linux Security Tools MCP Server MCP server in PolicyLayer and add a rule for john_crack: 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 Linux Security Tools MCP Server. Nothing to install.

What risk level is john_crack? +

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

Can I rate-limit john_crack? +

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

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

john_crack is provided by the Kali Linux Security Tools MCP Server MCP server (jesseeikeland/kali-linux-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.