This document outlines the comprehensive security enhancements implemented for the Python2Cpp project to address critical vulnerabilities.

• Input Size Limits: Maximum 10KB Python code input
• AST Node Limits: Maximum 1000 AST nodes to prevent resource exhaustion
• Pydantic Validation: Server-side input validation with size constraints
• Dangerous Import Detection: Basic heuristic to detect potentially unsafe imports

• File Size Validation: Maximum 50KB file size limit
• Path Validation: Comprehensive file path validation to prevent directory traversal
• Input Sanitization: Secure handling of user input and file paths

• Client-side Validation: Pre-validates input before sending to server
• File Upload Restrictions: Type and size validation for uploads
• Content Size Checking: Validates content size after file reading

• Reduced Limits: Changed from 10/minute to 3/minute for API endpoints
• Per-IP Tracking: Monitors individual IP addresses for abuse patterns
• Progressive Penalties: Implements exponential backoff with temporary bans

• Strike System: 5 strikes before temporary ban
• Ban Duration: 5-minute temporary bans for repeat offenders
• Comprehensive Logging: All security events are logged for monitoring

• Directory Traversal Protection: Validates and resolves file paths securely
• Secure Temporary Files: Uses secure temporary file creation methods
• Output Directory Validation: Ensures output files stay within safe boundaries

• Extension Checking: Only allows .py files for input
• Size Limits: Enforces file size restrictions at multiple levels
• Content Validation: Validates file content after reading

• Information Disclosure Prevention: Removes sensitive information from error messages
• Debug Mode Handling: Provides detailed errors only in debug mode
• Generic Error Messages: Uses safe, generic messages for production

• Comprehensive Logging: All security events are logged with timestamps
• IP Tracking: Logs IP addresses for security monitoring
• Structured Logging: Uses consistent format for easy parsing

• Content Security Policy: Implements strict CSP headers
• XSS Protection: Enables browser XSS protection
• Content Type Protection: Prevents MIME sniffing attacks
• Frame Options: Prevents clickjacking attacks

• Restricted Origins: Changed from wildcard "*" to specific allowed origins
• Method Restrictions: Only allows necessary HTTP methods
• Header Restrictions: Limits allowed headers for security

• Real-time Validation: Validates input as user types
• File Upload Security: Comprehensive file validation for uploads
• Drag and Drop Security: Secure handling of drag and drop operations

• Timeout Handling: 30-second timeout for API requests
• Error Sanitization: Cleans error messages before display
• User-friendly Messages: Provides clear, safe error messages

SECURITY_CONFIG = {
    'MAX_INPUT_SIZE': 10 * 1024,        # 10KB max Python code
    'MAX_AST_NODES': 1000,              # Max AST nodes
    'MAX_FILE_SIZE': 50 * 1024,         # 50KB max file size
    'API_RATE_LIMIT': '3/minute',       # API rate limit
    'CONVERSION_TIMEOUT': 30,           # Conversion timeout
    'ALLOWED_ORIGINS': [...],           # Allowed CORS origins
    'CSP_HEADER': "...",               # Content Security Policy
}

• validate_input_size(): Validates input size limits
• validate_ast_complexity(): Checks AST node count limits
• sanitize_filename(): Prevents path traversal attacks
• validate_file_path(): Comprehensive file path validation
• sanitize_error_message(): Removes sensitive information from errors

• Implements timeout mechanisms for long-running operations
• Prevents resource exhaustion from infinite loops or complex operations

• Input size and complexity validation tests
• Path traversal protection tests
• Error message sanitization tests
• CLI security feature tests

• API rate limiting verification
• File upload security tests
• CORS and security header validation

All security enhancements maintain backward compatibility:

• Existing CLI usage patterns continue to work
• API responses maintain same structure (with added security)
• Configuration is additive, not replacing existing functionality

• All security violations are logged to security.log
• Includes IP addresses, timestamps, and violation details
• Structured format for easy parsing and analysis

1. Monitor security.log for suspicious patterns
2. Set up alerts for repeated violations from same IP
3. Regularly review file size and complexity limits
4. Monitor API response times for performance impact

• Ensure PROD = True in constants.py
• Set up log rotation for security.log
• Configure firewall rules based on security logs
• Regularly review and update CORS allowed origins

• Input validation adds minimal overhead
• Rate limiting may affect high-volume users
• Security logging has minimal performance impact
• File size limits prevent resource exhaustion

1. Integration with Web Application Firewall (WAF)
2. Advanced malware scanning for uploaded files
3. Machine learning-based anomaly detection
4. Integration with security monitoring tools
5. Advanced rate limiting with different tiers

• Regularly review security logs for new attack patterns
• Update dangerous import patterns based on threats
• Adjust rate limits based on usage patterns
• Keep security headers updated with latest recommendations