mcpaudit 0.5.0

Static security scanner for MCP servers — Python + TypeScript/JavaScript, zero dependencies, 36 rules

mcpaudit

Static security scanner for MCP servers -- zero dependencies, AST-based, 20 rules, <200ms.

python 3.11+ | zero dependencies | MIT license

---

Quick Start

# Install
pip install -e .

# Scan a file
mcpaudit /path/to/server.py

# Scan a directory
mcpaudit /path/to/mcp-servers/

# JSON output for CI/CD
mcpaudit /path/to/server.py --format json

# HTML report
mcpaudit /path/to/server.py --format html --output report.html

# SARIF output (GitHub Code Scanning, VS Code SARIF Viewer)
mcpaudit /path/to/server.py --format sarif -o results.sarif

# Generate default config file
mcpaudit --init

Why mcpaudit?

	AI-Infra-Guard (Tencent)	mcpaudit
Requirements	Docker + 4GB RAM + LLM API key	Python 3.11+ (stdlib only)
Speed	Minutes (API calls)	<200ms (static analysis)
Method	ReAct agent with LLM	AST + regex pattern matching
Cost	LLM API calls	$0 (everything local)
Dependencies	Docker, LLM SDK	None (stdlib only)
CI/CD	Manual	Exit codes + JSON + HTML + SARIF

Security Rules (20)

Every finding includes a CWE reference for standards traceability and a confidence level (HIGH, MEDIUM, or LOW) indicating detection accuracy.

Rule ID	Severity	What it Detects	CWE
CMD-001	CRITICAL	Command injection -- subprocess with shell=True	CWE-78
CMD-002	HIGH	Command injection -- subprocess with f-strings or string concatenation	CWE-78
SQL-001	CRITICAL	SQL injection -- queries with string interpolation	CWE-89
SEC-001	CRITICAL	Hardcoded secrets -- API keys, tokens, passwords in source code	CWE-798
DESER-001	CRITICAL	Unsafe deserialization -- yaml.load(), arbitrary code execution	CWE-502
PATH-001	HIGH	Path traversal -- file operations on user input without resolve()/is_relative_to()	CWE-22
PATH-002	MEDIUM	Hardcoded absolute paths -- /Users/, /home/, C:\Users\	--
PERM-001	HIGH	Excessive permissions (chmod 777)	CWE-250
AUTH-001	MEDIUM	Missing authentication in server code	CWE-306
CORS-001	MEDIUM	CORS wildcard (Access-Control-Allow-Origin: *)	CWE-942
VAL-001	MEDIUM	Missing input validation in MCP handler functions	--
REDOS-001	MEDIUM	ReDoS -- regex with nested quantifiers	--
RATE-001	LOW	Missing rate limiting in server code	CWE-770
TEMP-001	LOW	Insecure temporary file creation	CWE-377
SSRF-001	HIGH	Server-Side Request Forgery -- HTTP requests with dynamic URLs	CWE-918
FILE-001	HIGH	Unsafe file write -- open() with dynamic path in write mode	CWE-73
ERR-001	MEDIUM	Missing error handling in MCP tool handler functions	CWE-755
LOG-001	MEDIUM	Sensitive data in logs -- logging secrets, tokens, passwords	CWE-532
RES-001	MEDIUM	Resource exhaustion -- unbounded reads, missing timeouts	CWE-400
INFO-001	LOW	Information disclosure -- detailed exceptions returned to users	--

Configuration File

mcpaudit supports a .mcpaudit.yml configuration file for persistent project-level settings.

Generate default config

mcpaudit --init

This creates a .mcpaudit.yml in the current directory with all options commented out.

Use a custom config

mcpaudit /path/to/code --config .mcpaudit.yml

If no --config flag is passed, mcpaudit automatically loads .mcpaudit.yml from the current working directory when present.

Configuration options

# .mcpaudit.yml

# Disable specific rules by ID
exclude_rules:
  - AUTH-001
  - RATE-001

# Skip files/directories matching these glob patterns
exclude_paths:
  - "tests/*"
  - "vendor/*"

# Only show findings at or above this severity level
# Values: critical, high, medium, low, info
severity_threshold: medium

# Default output format: text, json, html, sarif
output_format: text

CLI flags (--format, --severity) override config file values when both are specified.

Output Formats

Terminal (default)

============================================================
  MCP Security Audit -- Resultados
============================================================
  Archivos escaneados: 1
  Lineas escaneadas: 150
  Hallazgos totales: 3
============================================================

  [FILE] server.py
     Grade: C | 3 hallazgos | 12.3ms

     [!!] [CMD-001] Command Injection (shell=True)
       Linea 42: subprocess.run() con shell=True.
       Codigo: subprocess.run(cmd, shell=True)
       Fix: Usar lista de argumentos sin shell=True.

     [!] [PATH-001] Posible Path Traversal
       Linea 18: Funcion open() sin validacion de path.
       Fix: Usar path.resolve() y path.is_relative_to(base_dir).

     [-] [AUTH-001] Sin autenticacion detectada
       Linea 1: El servidor MCP no implementa autenticacion.
============================================================

JSON (for CI/CD)

{
  "summary": {
    "files_scanned": 1,
    "total_findings": 3,
    "overall_grade": "C",
    "severity_counts": {
      "CRITICAL": 1,
      "HIGH": 1,
      "MEDIUM": 1,
      "LOW": 0,
      "INFO": 0
    },
    "exit_code": 2
  },
  "results": [...]
}

Each finding in results includes cwe (e.g., "CWE-78") and confidence (e.g., "HIGH") fields.

HTML Report

Self-contained dark-themed HTML with dashboard, severity breakdown, and detailed findings. Generate with:

mcpaudit /path/to/code --format html --output report.html

SARIF (Static Analysis Results Interchange Format)

SARIF 2.1.0 output for integration with industry-standard tooling:

• GitHub Code Scanning -- upload via github/codeql-action/upload-sarif
• VS Code SARIF Viewer -- view findings inline in your editor
• Azure DevOps -- native SARIF support in pipelines
• Any SARIF-compatible viewer -- standard OASIS format

mcpaudit /path/to/code --format sarif -o results.sarif

Each SARIF result includes security-severity scores (0--10 scale), CWE tags, confidence-based precision levels, and inline fix suggestions.

Upload to GitHub Code Scanning

# In your GitHub Actions workflow
- run: mcpaudit . --format sarif -o results.sarif
- uses: github/codeql-action/upload-sarif@v3
  with:
    sarif_file: results.sarif

Grading System

Grade	Weighted Score	Meaning
A+	0	No findings
A	1-2	Minor issues only
B	3-5	Some medium issues
C	6-10	High severity findings
D	11-20	Multiple high severity
F	21+	Critical issues present

Exit Codes

Code	Meaning
0	No HIGH or CRITICAL findings
1	HIGH findings present
2	CRITICAL findings present

CI/CD Integration

GitHub Actions

# .github/workflows/security.yml
name: Security Scan
on: [push, pull_request]

jobs:
  scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.11'
      - run: pip install -e path/to/mcpaudit
      - run: mcpaudit . --format json --output results.json
      - run: mcpaudit . --format html --output report.html
      - run: mcpaudit . --format sarif --output results.sarif
      - uses: actions/upload-artifact@v4
        with:
          name: security-report
          path: |
            report.html
            results.json
      - uses: github/codeql-action/upload-sarif@v3
        if: always()
        with:
          sarif_file: results.sarif

A reusable workflow is included at .github/workflows/security-scan.yml.

Pre-commit Hook

cp hooks/pre-commit .git/hooks/pre-commit
chmod +x .git/hooks/pre-commit

Blocks commits with HIGH or CRITICAL findings.

Baseline (Suppress Known Findings)

Accept existing findings to only fail on new security issues:

# Step 1: Create baseline from current state
mcpaudit . --create-baseline .mcpaudit-baseline.json

# Step 2: In CI/CD, scan with baseline — only NEW findings trigger failure
mcpaudit . --baseline .mcpaudit-baseline.json

Fingerprints are stable across line number changes — a finding is only un-suppressed if the code itself changes.

Architecture

mcpaudit/
|
|-- __init__.py          # Package exports (MCPSecurityScanner, models)
|-- __main__.py          # CLI entry point (mcpaudit command)
|-- scanner.py           # Core scanning engine
|-- models.py            # Data classes (Finding, ScanResult, Severity, etc.)
|-- formatters.py        # Text and JSON output formatters
|-- config.py            # Configuration file loader (.mcpaudit.yml)
|
|-- rules/               # Modular security rules (20 rules)
|   |-- __init__.py      # Rule base class + get_all_rules()
|   |-- path_traversal.py
|   |-- command_injection.py
|   |-- hardcoded_secrets.py
|   |-- absolute_paths.py
|   |-- input_validation.py
|   |-- sql_injection.py
|   |-- unsafe_deser.py
|   |-- info_disclosure.py
|   |-- missing_auth.py
|   |-- cors_misconfig.py
|   |-- unsafe_temp.py
|   |-- excessive_perms.py
|   |-- redos.py
|   |-- rate_limiting.py
|   |-- ssrf.py           # SSRF detection
|   |-- unsafe_file_write.py # Dynamic path write detection
|   |-- error_handling.py  # Missing try/except in tool handlers
|   |-- sensitive_logging.py # Secrets in log statements
|   |-- resource_exhaustion.py # Unbounded reads, missing timeouts
|
|-- reporters/           # Report generators
|   |-- html_reporter.py # Self-contained HTML report (dark theme)
|   |-- sarif_reporter.py # SARIF 2.1.0 output (GitHub, VS Code, etc.)
|
|
|-- examples/           # Demo files
|   |-- vulnerable_server.py  # Intentionally vulnerable MCP server (26 findings)
|
tests/
|   |-- test_scanner.py    # Core scanner tests
|   |-- test_sarif.py      # SARIF output validation
|   |-- test_config.py     # Config file tests
|   |-- test_new_rules.py  # Tests for SSRF, FILE, ERR, LOG, RES rules
|
hooks/
|   |-- pre-commit       # Git pre-commit hook
|
.github/workflows/
    |-- security-scan.yml  # Reusable GitHub Actions workflow

CWE Reference Table

All rule CWE mappings at a glance:

Rule ID	CWE ID	CWE Name
CMD-001, CMD-002	CWE-78	OS Command Injection
SQL-001	CWE-89	SQL Injection
AUTH-001	CWE-306	Missing Authentication for Critical Function
PATH-001	CWE-22	Path Traversal
DESER-001	CWE-502	Deserialization of Untrusted Data
CORS-001	CWE-942	Overly Permissive Cross-domain Whitelist
RATE-001	CWE-770	Allocation of Resources Without Limits
PERM-001	CWE-250	Execution with Unnecessary Privileges
TEMP-001	CWE-377	Insecure Temporary File
SEC-001	CWE-798	Use of Hard-coded Credentials
SSRF-001	CWE-918	Server-Side Request Forgery
FILE-001	CWE-73	External Control of File Name or Path
ERR-001	CWE-755	Improper Handling of Exceptional Conditions
LOG-001	CWE-532	Insertion of Sensitive Information into Log File
RES-001	CWE-400	Uncontrolled Resource Consumption

Adding Custom Rules

from mcpaudit.rules import Rule
from mcpaudit.models import Finding, Severity

class MyCustomRule(Rule):
    @property
    def rule_id(self) -> str:
        return "CUSTOM-001"

    @property
    def name(self) -> str:
        return "My Custom Check"

    @property
    def severity(self) -> Severity:
        return Severity.HIGH

    @property
    def description(self) -> str:
        return "Detects my custom pattern."

    def check(self, tree, source) -> list[Finding]:
        findings = []
        # Your detection logic here
        return findings

# Use it
from mcpaudit.scanner import MCPSecurityScanner
scanner = MCPSecurityScanner(rules=[MyCustomRule()])

License

MIT License. Created by Carlos Miret.