mcpsec 2.0.1

Security scanner and protocol fuzzer for MCP (Model Context Protocol) servers. Found and reported vulnerabilities in official Anthropic and GitHub MCP implementations.

mcpsec

Security scanner and protocol fuzzer for MCP servers.

Most MCP security tools do static analysis. mcpsec connects to live servers and proves exploitation.

Installation • Usage • Scanners • Fuzzing

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Why mcpsec?

MCP is the protocol connecting AI agents (Claude, Cursor, VS Code) to external tools. Every major AI company uses it. Its security is often overlooked.

• 82% of MCP implementations have path traversal vulnerabilities
• 67% are vulnerable to code injection
• ~2,000 internet-exposed MCP servers found with zero authentication
• Anthropic's own Git MCP server had 3 critical RCE vulnerabilities

mcpsec has been used to discover and report 5 vulnerabilities across Anthropic and GitHub MCP implementations, affecting Python, TypeScript, and Go SDK ecosystems.

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Installation

pip install mcpsec

For AI-powered features:

pip install mcpsec[ai]

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Usage

Runtime Scanning

# Scan via stdio
mcpsec scan --stdio "npx @modelcontextprotocol/server-filesystem /tmp"

# Scan via HTTP with auth
mcpsec scan --http http://localhost:8080/mcp -H "Authorization: Bearer TOKEN"

# Enumerate attack surface
mcpsec info --stdio "python my_server.py"

Protocol Fuzzing

# Standard fuzzing (150+ cases)
mcpsec fuzz --stdio "python my_server.py"

# High intensity (500+ cases)
mcpsec fuzz --stdio "python my_server.py" --intensity high

# Target specific attack class
mcpsec fuzz --stdio "python my_server.py" -g protocol_state_machine
mcpsec fuzz --stdio "python my_server.py" -g id_confusion

# AI-powered payload generation
mcpsec fuzz --stdio "python my_server.py" --ai

Static Analysis

# Local source
mcpsec audit --path ./my-mcp-server

# GitHub repository
mcpsec audit --github https://github.com/user/mcp-server

# With AI validation
mcpsec audit --github https://github.com/user/mcp-server --ai

Rogue Server (Client Testing)

# Test MCP clients for vulnerabilities
mcpsec rogue-server --port 9999 --attack all

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Scanners

Scanner	Description
prompt-injection	Hidden instructions in tool descriptions
command-injection	OS command injection with proof of exploitation
path-traversal	File traversal with proof of exploitation
ssrf	Server-Side Request Forgery to internal services
auth-audit	Missing auth, dangerous tool combinations
description-prompt-injection	LLM manipulation via descriptions
resource-ssrf	SSRF via MCP resource URIs
capability-escalation	Undeclared capability abuse

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Fuzz Generators

Generator	Description
malformed_json	Invalid JSON structures
protocol_violation	JSON-RPC spec violations
type_confusion	Type mismatch attacks
unicode_attacks	Encoding edge cases
injection_payloads	SQLi, XSS, command injection
protocol_state_machine	MCP state violations
id_confusion	JSON-RPC ID edge cases

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Semgrep Rules

49 MCP-specific rules:

• Command injection (exec, spawn, child_process)
• SQL injection (raw queries, ORM bypass)
• Path traversal (path.join with unsanitized input)
• Description injection (dynamic tool descriptions)
• Resource URI issues (SSRF vectors)
• Protocol handler vulnerabilities

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Configuration

AI Provider Setup

mcpsec setup

Supports: OpenAI, Anthropic, Google, Groq, DeepSeek, Ollama

Output Formats

# JSON
mcpsec scan --stdio "server" --output results.json

# SARIF (CI/CD)
mcpsec fuzz --stdio "server" --output results.sarif

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How It Works

┌─────────┐     MCP Protocol      ┌────────────┐
│ mcpsec  │ ◄──── JSON-RPC ────►  │   Target   │
│         │    (stdio / HTTP)     │   Server   │
└────┬────┘                       └────────────┘
     │
     ├── Connect & enumerate attack surface
     ├── Run static scanners
     ├── Generate dynamic payloads  
     ├── Execute fuzzing campaigns
     └── Report findings with evidence

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Disclaimer

For authorized security testing only. Only scan servers you own or have permission to test.

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License

MIT

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Built by Manthan Ghasadiya