kill_session

THE RISK

Critical Risk

Why kill_session needs a policy

Terminating a tmux session is an irreversible destructive action; any unsaved state, running processes (e.g., Metasploit sessions, reverse shells), and session history are permanently lost. In a penetration testing context, this could destroy active exploit sessions or ongoing workflows that cannot be recovered.

From the tool's definition 'Terminate a tmux session' — irreversibly kills a running session, destroying its state, history, and any running processes within it.

Documented attack patterns abuse exactly the kind of access kill_session gives an agent:

POLICY

How to control kill_session

PolicyLayer is an MCP gateway — it sits between your AI agents and Pentest MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for kill_session:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "kill_session"
  ]
}

kill_session disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Pentest MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Pentest MCP Server tools

Execute execute Execute a command in a persistent tmux session with trigger-based monitoring Execute recover_sessions Find and reconnect to orphaned tmux sessions Execute create_session Create a new persistent tmux session Execute send_input Send input to an interactive session Write upload_file Upload a file to the your OS system Read parse_tool_output Parse common pentest tool outputs (nmap XML, JSON, etc.) Read download_file Download a file from the your OS system Read get_session_history Get command history for a specific tmux session

All 12 Pentest MCP Server tools →

Destructive tools on other servers

Android Forensics ADB MCP Server create_full_backup 0xarchive web3_revoke_key Frida Game Hacking MCP clear_scan cPanel MCP Server clear_spam_box

Go deeper

Critical-risk tools in Pentest MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about kill_session

What does the kill_session tool do? +

Terminate a tmux session. It is categorised as a Destructive tool in the Pentest MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on kill_session? +

Register the Pentest MCP Server MCP server in PolicyLayer and add a rule for kill_session: 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 Pentest MCP Server. Nothing to install.

What risk level is kill_session? +

kill_session is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit kill_session? +

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

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

kill_session is provided by the Pentest MCP Server MCP server (layesec006/pentest-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Pentest MCP Server tool call.

Start from Pentest MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →