MCP Time Server Node

# Recurrence Refactor Security Audit **Date**: 2025-01-29 **Components**: RecurrenceValidator, RecurrenceFactory, and all Recurrence pattern implementations ## Security Checks Performed ### 1. Input Validation ✅ - **String Length Limits**: Timezone strings limited to 100 characters (LIMITS.MAX_TIMEZONE_LENGTH) - **Pattern Validation**: Only accepts 'daily', 'weekly', 'monthly', 'yearly' - no arbitrary strings - **Time Format**: Strict regex `/^(\d{1,2}):(\d{2})$/` prevents injection - **Integer Bounds**: - dayOfWeek: 0-6 only - dayOfMonth: 1-31 or -1 (last day) - month: 0-11 only ### 2. Injection Prevention ✅ - **SQL Injection**: Pattern validation prevents SQL in pattern field - **XSS Prevention**: No HTML/script tags accepted in any field - **Path Traversal**: No file system operations performed - **Prototype Pollution**: No dynamic property access on objects ### 3. Regular Expression Safety ✅ - **Time Regex**: `/^(\d{1,2}):(\d{2})$/` is linear - no ReDoS vulnerability - **No Complex Patterns**: All validation uses simple, non-backtracking patterns ### 4. Dangerous Functions ✅ - **No eval()**: Code does not use eval - **No Function()**: No dynamic function construction - **No innerHTML**: Server-side code, no DOM manipulation - **No exec()**: No shell command execution ### 5. Error Handling ✅ - **No Path Leakage**: Errors don't expose file system paths - **No Stack Traces**: Structured errors with specific codes - **Limited Details**: Only necessary information in error responses ### 6. Dependency Security ✅ - **npm audit**: 0 vulnerabilities found - **date-fns**: Well-maintained, security-conscious library - **date-fns-tz**: Official timezone extension ## Security Test Results ``` ✅ Timezone length validation (100 char limit) ✅ Pattern injection protection (SQL, XSS, null bytes) ✅ Time format injection protection ✅ Integer overflow protection ✅ No dangerous function usage ✅ No sensitive information leakage ``` ## Recommendations 1. **Continue Current Practices**: - Input validation on all user inputs - String length limits to prevent DoS - Whitelist approach for pattern validation 2. **For Integration Phase**: - Maintain same validation standards - Consider adding rate limiting if not already present - Ensure caching doesn't bypass validation 3. **Future Considerations**: - Consider adding input sanitization logs for security monitoring - Document security boundaries in API documentation ## Conclusion The recurrence refactor implementation follows security best practices: - All inputs are validated and bounded - No dangerous operations are performed - Error messages are safe - Dependencies are secure No security vulnerabilities were identified in the refactored code.