database_query · Vulnerable MCP Server MCP: Risk & Policy

WHAT IT DOES

What database_query does on Vulnerable MCP Server

AI agents invoke database_query to trigger actions in Vulnerable MCP Server. 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 IT NEEDS A POLICY

Why database_query needs a policy

This tool executes arbitrary SQL queries, which can encompass SELECT (Read), INSERT/UPDATE (Write), DELETE/DROP (Destructive), and even system-level commands via SQL injection or stored procedures. In a deliberately insecure server context with no implied input sanitization, the blast radius is critical.

From the tool's definition 'Execute a SQL query against the internal user database' — arbitrary SQL execution against an internal database in a deliberately insecure pentest lab server

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

database_query Rate-limited

database_query 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "database_query": {
      "limits": [
        {
          "counter": "database_query_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about database_query

What does the database_query tool do? +

Execute a SQL query against the internal user database. It is categorised as a Execute tool in the Vulnerable MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on database_query? +

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

What risk level is database_query? +

database_query is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit database_query? +

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

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

database_query is provided by the Vulnerable MCP Server MCP server (joyghoshs/vulnerable-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.