crack_john
Offline password cracking using John the Ripper. Hashes written to temp file.
This record as markdown: /tools/0xmihirk-hercules-mcp/crack-john.md
What crack_john does on Hercules MCP
AI agents invoke crack_john 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.
Why crack_john is rated High
This tool triggers execution of a complex external program (John the Ripper) to perform cryptanalytic operations. While password cracking itself does not directly modify or destroy data on the target system, it is a runtime execution of a powerful offensive security tool whose effects (password recovery) depend entirely on the arguments provided.
From the tool's definition Tool performs 'offline password cracking using John the Ripper' — executes a specialized cryptographic attack tool whose outcomes depend on supplied hash inputs and wordlist arguments.
Attacks that exploit this kind of access
The rule that runs crack_john 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 crack_john, this is the rule to start with:
crack_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.
The button opens the PolicyLayer dashboard: create your workspace, connect Hercules MCP, apply this rule, and every crack_john call is checked against it from then on.
Questions about crack_john
Offline password cracking using John the Ripper. Hashes written to temp file. 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.
Register the Hercules MCP server in PolicyLayer and add a rule for crack_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 Hercules MCP. Nothing to install.
crack_john is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the crack_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.
Set action: deny in the PolicyLayer policy for crack_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.
crack_john 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.
More on Hercules, and thousands of servers like it.
Across the catalogue