python-sdk/pkg/hanzo-mcp/SECURITY_PATCH.md

Security Patch for Hanzo MCP v0.8.13

Critical Security Vulnerabilities Found

1. Command Injection (CRITICAL) 🚨

Location: hanzo_mcp/tools/shell/command_executor.py line 114 Issue: Insufficient shell escaping using basic string replacement Risk: Remote code execution

Current Code:

escaped_command = command.replace('"', '\\"')

Fixed Code:

import shlex
escaped_command = shlex.quote(command)

2. Path Traversal (HIGH) ⚠️

Location: hanzo_mcp/tools/common/permissions.py Issue: No validation for symlinks and ../ traversal Risk: Unauthorized file access

Add validation:

def validate_path(self, path: str) -> bool:
    """Validate path against traversal attacks."""
    resolved = Path(path).resolve()
    
    # Check for path traversal
    if ".." in str(path):
        return False
    
    # Check against allowed paths
    for allowed in self.allowed_paths:
        try:
            resolved.relative_to(allowed)
            return True
        except ValueError:
            continue
    
    return False

3. Missing Authentication (HIGH) ⚠️

Location: hanzo_mcp/server.py Issue: MCP server accepts any local connection without auth Risk: Unauthorized access to system

Add basic token auth:

import secrets
import os

class HanzoMCPServer:
    def __init__(self, ...):
        self.auth_token = os.environ.get('HANZO_MCP_TOKEN') or secrets.token_urlsafe(32)
        
    def verify_auth(self, request_token: str) -> bool:
        """Verify authentication token."""
        return secrets.compare_digest(request_token, self.auth_token)

4. Subprocess Timeout (MEDIUM)

Location: Multiple subprocess.run() calls Issue: Missing consistent timeout enforcement Risk: Resource exhaustion from hanging processes

Fix:

# Always use timeout
result = subprocess.run(
    command,
    timeout=self.command_timeout,  # Default 120s
    check=False,
    capture_output=True
)

Test Results Summary

• Total Tests: 410 collected
• Test Errors: 4 collection errors
• Status: Tests not fully passing due to environment issues
• Recommendation: Fix security issues first, then resolve test environment

Immediate Actions Required

1. Apply command injection patch using shlex.quote()
2. Add path validation to PermissionManager
3. Implement token authentication for MCP server
4. Add timeout to all subprocess calls
5. Add audit logging for all operations
6. Implement rate limiting to prevent abuse

Risk Assessment

Vulnerability	Severity	Exploitability	Impact	Priority
Command Injection	CRITICAL	High	RCE	P0
Path Traversal	HIGH	Medium	File Access	P1
No Authentication	HIGH	High	Unauthorized Access	P1
Missing Timeouts	MEDIUM	Low	DoS	P2

Deployment Recommendation

DO NOT DEPLOY TO PRODUCTION until:

1. All CRITICAL and HIGH severity issues are patched
2. Authentication is implemented
3. Test suite is passing (currently has environment issues)
4. Security audit is performed on patched version

Next Version Plan (v0.8.14)

Should include:

• Security patches for all identified vulnerabilities
• Authentication system
• Audit logging
• Rate limiting
• Improved error handling
• Complete test coverage

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Generated by Code Review Agent Date: 2024-12-20 Version Reviewed: hanzo-mcp v0.8.13