AI agents invoke tools_hydra to trigger actions in Zebbern Kali 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.
Hydra is a network login cracker used to perform brute-force attacks against authentication services. Even with an empty description, the tool name and server context make it highly likely this executes credential attacks against external systems. Misuse could compromise accounts across many protocols (SSH, FTP, HTTP, RDP, etc.), making severity critical.
From the tool's definition Tool name 'tools_hydra' on a Kali Linux penetration testing MCP server; Hydra is a well-known brute-force/credential-stuffing attack tool. Sibling tools include ad_password_spray, ad_secretsdump, ad_kerberoast — confirming offensive security context.
Documented attack patterns abuse exactly the kind of access tools_hydra gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Zebbern Kali MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for tools_hydra:
{
"version": "1",
"default": "deny",
"tools": {
"tools_hydra": {
"limits": [
{
"counter": "tools_hydra_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}tools_hydra 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.
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tools_hydra. It is categorised as a Execute tool in the Zebbern Kali MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Zebbern Kali MCP server in PolicyLayer and add a rule for tools_hydra: 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 Zebbern Kali MCP. Nothing to install.
tools_hydra 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 tools_hydra 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 tools_hydra. 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.
tools_hydra is provided by the Zebbern Kali MCP server (zebbern/zebbern-kali-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 128 Zebbern Kali MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
128 Zebbern Kali MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.