rubeus_kirbi · Rubeus MCP Server MCP: Risk & Policy

WHAT IT DOES

What rubeus_kirbi does on Rubeus MCP Server

AI agents use rubeus_kirbi to create or update resources in Rubeus MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Rubeus MCP Server environment.

WHY IT NEEDS A POLICY

Why rubeus_kirbi needs a policy

This tool modifies a Kerberos ticket file. While described as a Write operation (reversible modification of a file), in the context of a Kerberos abuse toolkit (Rubeus/Impacket), modifying kirbi tickets is a privilege escalation/lateral movement technique used to forge or alter authentication credentials.

From the tool's definition 'Modify a kirbi ticket' — modifies an existing Kerberos ticket (kirbi format)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

rubeus_kirbi Rate-limited

rubeus_kirbi stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "rubeus_kirbi": {
      "limits": [
        {
          "counter": "rubeus_kirbi_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Rubeus MCP Server, so you can run agents against it safely.

FAQ

Questions about rubeus_kirbi

What does the rubeus_kirbi tool do? +

Modify a kirbi ticket. It is categorised as a Write tool in the Rubeus MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on rubeus_kirbi? +

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

What risk level is rubeus_kirbi? +

rubeus_kirbi is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit rubeus_kirbi? +

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

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

rubeus_kirbi is provided by the Rubeus MCP Server MCP server (schwarztim/sec-rubeus-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.