Read the contents of a file from the server filesystem.
AI agents call read_file to retrieve information from Vulnerable MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a Read operation as it retrieves file contents without side effects. However, severity is elevated to 'high' rather than 'low' because on a deliberately vulnerable pentest lab server with sibling tools like 'get_user_data', 'get_tool_call_history', and 'list_environment', unrestricted file read access could expose sensitive configuration files, credentials, logs, or other confidential data.
From the tool's definition Tool name 'read_file' and description 'Read the contents of a file from the server filesystem' explicitly indicate data retrieval without modification. No deletion, creation, or execution is described.
Attacks that exploit this kind of access
Read the contents of a file from the server filesystem. It is categorised as a Read tool in the Vulnerable MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Vulnerable MCP Server MCP server in PolicyLayer and add a rule for read_file: 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.
read_file is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the read_file 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.
Set action: deny in the PolicyLayer policy for read_file. 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.
read_file 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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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