ssh_upload · MCP SSH Proxy MCP: Risk & Policy

WHAT IT DOES

What ssh_upload does on MCP SSH Proxy

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

WHY IT NEEDS A POLICY

Why ssh_upload needs a policy

The tool uploads files to remote SSH servers, which is a reversible write operation (files can be deleted or overwritten later). While it modifies remote system state, it does not irreversibly destroy data or execute arbitrary code. The severity is high due to potential blast radius if an agent uploads malicious or sensitive files to production servers, but the human-in-the-loop approval requirement mitigates risk.

From the tool's definition Tool named 'ssh_upload' with description 'Uploads a file to a configured SSH server via SFTP' - this creates or modifies data on remote systems.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ssh_upload Rate-limited

ssh_upload 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": {
    "ssh_upload": {
      "limits": [
        {
          "counter": "ssh_upload_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about ssh_upload

What does the ssh_upload tool do? +

Uploads a file to a configured SSH server via SFTP. Provide inline. It is categorised as a Write tool in the MCP SSH Proxy MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on ssh_upload? +

Register the MCP SSH Proxy MCP server in PolicyLayer and add a rule for ssh_upload: 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 MCP SSH Proxy. Nothing to install.

What risk level is ssh_upload? +

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

Can I rate-limit ssh_upload? +

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

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

ssh_upload is provided by the MCP SSH Proxy MCP server (quinbook/mcpsshproxy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.