Low Risk

cert_get

Get certificate details

How to control cert_get ↓

AI agents call cert_get to retrieve information from OPNSense MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

Low Risk

This tool retrieves certificate metadata or information from the OPNSense firewall. It performs a query operation without side effects, aligning with the Read category. The severity is low because retrieving certificate details poses minimal risk; it exposes no sensitive private key material (standard secure practice) and does not affect system configuration or operations.

From the tool's definition Tool name 'cert_get' with description 'Get certificate details' indicates a retrieval operation with no modification, deletion, or execution of external actions.

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

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "cert_get": {}
  }
}

cert_get is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

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

What does the cert_get tool do? +

Get certificate details. It is categorised as a Read tool in the OPNSense MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on cert_get? +

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

What risk level is cert_get? +

cert_get is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit cert_get? +

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

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

cert_get is provided by the OPNSense MCP Server MCP server (vespo92/opnsensemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every OPNSense MCP Server tool call.

Deterministic rules across all 196 OPNSense MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

196 OPNSense MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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