{
  "audit_metadata": {
    "timestamp": "2026-03-01T00:00:00Z",
    "project": "ESP32_ZACUS",
    "board": "ESP32-S3-WROOM-1-N16R8",
    "firmware_version": "freenove_esp32s3",
    "audit_scope": "Full embedded security analysis",
    "analyst": "Security Expert",
    "framework": "Arduino/PlatformIO"
  },
  "executive_summary": {
    "overall_risk_level": "HIGH",
    "critical_vulnerabilities": 2,
    "high_vulnerabilities": 3,
    "medium_vulnerabilities": 4,
    "low_vulnerabilities": 3,
    "findings_summary": "Multiple security issues identified including hardcoded credentials, missing authentication, and unsafe input handling. Immediate remediation required for production deployment."
  },
  "vulnerabilities": [
    {
      "id": "CRIT-001",
      "title": "Hardcoded WiFi Credentials in Configuration",
      "severity": "CRITICAL",
      "category": "Credentials & Secrets",
      "cwe": "CWE-798: Use of Hard-Coded Credentials",
      "location": {
        "file": "ui_freenove_allinone/src/storage_manager.cpp",
        "lines": [52],
        "component": "APP_WIFI.json embedded configuration"
      },
      "description": "WiFi credentials (SSID and password) are hardcoded in the firmware as embedded JSON configuration strings. Multiple credential sets found with weak passwords.",
      "code_snippet": "{\n  \"local_ssid\": \"Les cils\",\n  \"local_password\": \"mascarade\",\n  \"test_ssid\": \"Les cils\",\n  \"test_password\": \"mascarade\",\n  \"ap_default_ssid\": \"Freenove-Setup\",\n  \"ap_default_password\": \"mascarade\"\n}",
      "affected_credentials": [
        {
          "type": "local_wifi",
          "ssid": "Les cils",
          "password": "mascarade",
          "usage": "Primary WiFi connection target"
        },
        {
          "type": "fallback_ap",
          "ssid": "Freenove-Setup",
          "password": "mascarade",
          "usage": "Access Point when no known WiFi available"
        }
      ],
      "attack_vectors": [
        "Firmware extraction via JTAG/UART",
        "Reverse engineering of binary",
        "WiFi network compromise with revealed credentials",
        "Brute force attacks using weak password"
      ],
      "impact": "Complete WiFi network compromise, unauthorized device access, local network intrusion",
      "remediation_steps": [
        "Move credentials to encrypted NVS (Non-Volatile Storage) with per-device unique values",
        "Implement secure credential provisioning via QR code or BLE during setup",
        "Use strong passwords (16+ chars, mixed case, symbols)",
        "Never commit credentials in firmware images",
        "Implement credential rotation mechanism"
      ],
      "references": [
        "OWASP: Hardcoded Credentials",
        "CWE-798",
        "ESP32 Security Best Practices"
      ]
    },
    {
      "id": "CRIT-002",
      "title": "Unauthenticated Web API Endpoints",
      "severity": "CRITICAL",
      "category": "Access Control",
      "cwe": "CWE-306: Missing Authentication for Critical Function",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [2007, 2011, 2015, 2019, 2023, 2100, 2105, 2110, 2130, 2140, 2145],
        "component": "Web API endpoints registration"
      },
      "description": "All Web API endpoints including critical control operations (unlock, WiFi connect, ESP-NOW send, camera control) are exposed without any authentication mechanism. Any client on the network can invoke arbitrary operations.",
      "exposed_endpoints": [
        {
          "path": "/api/scenario/unlock",
          "method": "POST",
          "function": "dispatchScenarioEventByName(\"UNLOCK\", now_ms)",
          "risk": "CRITICAL - Allows bypassing game logic/security mechanisms"
        },
        {
          "path": "/api/scenario/next",
          "method": "POST",
          "function": "notifyScenarioButtonGuarded",
          "risk": "HIGH - Skips game progression steps"
        },
        {
          "path": "/api/wifi/disconnect",
          "method": "POST",
          "function": "webScheduleStaDisconnect()",
          "risk": "HIGH - Device isolation/DoS"
        },
        {
          "path": "/api/wifi/connect",
          "method": "POST",
          "function": "g_network.connectSta(ssid, password)",
          "risk": "HIGH - MITM potential, credential injection"
        },
        {
          "path": "/api/network/espnow/on",
          "method": "POST",
          "function": "g_network.enableEspNow()",
          "risk": "HIGH - Enables unprotected wireless protocol"
        },
        {
          "path": "/api/espnow/send",
          "method": "POST",
          "function": "g_network.sendEspNowTarget(target, payload)",
          "risk": "CRITICAL - Arbitrary command injection to other devices"
        },
        {
          "path": "/api/camera/snapshot.jpg",
          "method": "GET",
          "function": "Camera snapshot capture",
          "risk": "MEDIUM - Privacy violation, information disclosure"
        },
        {
          "path": "/api/media/record/start",
          "method": "POST",
          "function": "g_media.startRecording()",
          "risk": "MEDIUM - Audio recording without consent"
        },
        {
          "path": "/api/hardware/led",
          "method": "POST",
          "function": "Hardware LED control",
          "risk": "LOW - Aesthetic but confirms vulnerability"
        }
      ],
      "attack_scenario": "An attacker on the local WiFi network can:\n1. Scan for port 80 (HTTP)\n2. Discover the Zacus device\n3. POST to /api/scenario/unlock to bypass game logic\n4. POST to /api/espnow/send to inject commands across ESP-NOW mesh\n5. Access /api/camera/snapshot.jpg for video surveillance\n6. POST to /api/wifi/connect to redirect device to attacker's network",
      "remediation_steps": [
        "Implement HMAC-SHA256 request signing with shared secret",
        "Add bearer token authentication via Authorization header",
        "Use mutual TLS (mTLS) for encrypted communication",
        "Implement rate limiting per IP address",
        "Add CORS restrictions to localhost only",
        "Disable HTTP, use HTTPS only",
        "Implement session tokens with timeout",
        "Add operation-level permission checking"
      ],
      "references": [
        "OWASP Top 10: A01 Broken Access Control",
        "CWE-306, CWE-352"
      ]
    },
    {
      "id": "HIGH-001",
      "title": "Unsafe Integer Parsing with sscanf",
      "severity": "HIGH",
      "category": "Input Validation",
      "cwe": "CWE-77: Improper Neutralization of Special Elements",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [1807],
        "function": "dispatchControlAction() - HW_LED_SET handler"
      },
      "description": "User-supplied color values are parsed with sscanf without proper input validation. Integer overflow/underflow can occur in RGB and brightness values.",
      "vulnerable_code": "const int count = std::sscanf(args.c_str(), \"%d %d %d %d %d\", &r, &g, &b, &brightness, &pulse);\nif (count < 3) { /* return error */ }\n// Missing: bounds checking before casting to uint8_t\nreturn g_hardware.setManualLed(static_cast<uint8_t>(r), ...);",
      "attack_vector": "POST /api/hardware/led with payload: 'HW_LED_SET 999999999 999999999 999999999 999999999'\nResult: Integer overflow when casting to uint8_t",
      "impact": "Unexpected LED behavior, potential PWM controller confusion, DoS via resource exhaustion",
      "remediation_steps": [
        "Validate parsed integers are within range [0-255] BEFORE casting",
        "Use strtol() with proper error handling instead of sscanf",
        "Implement safe integer parsing wrapper function",
        "Add compile-time integer overflow detection (-ftrapv flag)"
      ],
      "code_fix": "if (brightness < 0) brightness = 0;\nelse if (brightness > 255) brightness = 255;\n// ... repeat for r, g, b ... (Already present but demonstrates fix)"
    },
    {
      "id": "HIGH-002",
      "title": "Missing Request Validation in JSON Parsing",
      "severity": "HIGH",
      "category": "Input Validation",
      "cwe": "CWE-20: Improper Input Validation",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [654, 1239],
        "function": "executeEspNowCommandPayload(), webParseJsonBody()"
      },
      "description": "JSON payloads are deserialized without validation of document size limits or schema conformance. Malformed JSON could cause out-of-memory or unexpected behavior.",
      "code_snippet": "const DeserializationError error = deserializeJson(*out_document, body);\nreturn !error;  // Only checks for parse error, not content validation",
      "attack_scenario": "1. Send deeply nested JSON object to /api/espnow endpoint\n2. Trigger memory exhaustion in ArduinoJson parser\n3. Cause device reset/DoS",
      "impact": "Denial of Service, unpredictable behavior, potential stack overflow",
      "remediation_steps": [
        "Validate JSON document size before parsing",
        "Implement schema validation using StaticJsonDocument size limits",
        "Add JSON depth limits to prevent nested object attacks",
        "Implement request size limits (max 4KB recommended)",
        "Add timeout on JSON parsing operations"
      ]
    },
    {
      "id": "HIGH-003",
      "title": "Path Traversal Risk in File Operations",
      "severity": "HIGH",
      "category": "Path Traversal",
      "cwe": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory",
      "location": {
        "file": "ui_freenove_allinone/src/storage_manager.cpp",
        "lines": [308, 314],
        "function": "normalizeAbsolutePath(), loadTextFile()"
      },
      "description": "File path normalization only ensures paths start with '/' but does not prevent directory traversal attacks using '../' sequences. User can potentially read arbitrary files from the filesystem.",
      "code_snippet": "String normalizeAbsolutePath(const char* path) const {\n  String normalized = path;\n  if (!normalized.startsWith(\"/\")) {\n    normalized = \"/\" + normalized;  // Only prepends /, no '../' validation\n  }\n  return normalized;\n}",
      "attack_scenario": "1. Attacker calls /api/media/files?kind=music\n2. listFiles() uses user-supplied path parameter\n3. Send path='../../story/apps/APP_WIFI.json'\n4. Read WiFi configuration with credentials (though alreadyexposed via hardcoding)",
      "impact": "Information disclosure, sensitive file access, potential credential leakage",
      "remediation_steps": [
        "Implement whitelist of allowed base directories",
        "Use realpath() to resolve and validate complete paths",
        "Check for '../' sequences and reject them",
        "Implement chroot-style restriction to /data/",
        "Use filesystem layers with permission inheritance"
      ]
    },
    {
      "id": "MED-001",
      "title": "Weak Serial Command Parsing",
      "severity": "MEDIUM",
      "category": "Input Validation",
      "cwe": "CWE-78: Improper Neutralization of Special Elements in OS Command Execution",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [350-450],
        "function": "normalizeEventTokenFromText()"
      },
      "description": "Serial commands are parsed using string manipulation with limited validation. Command injection is possible through specially crafted event names.",
      "vulnerable_pattern": "if (startsWithIgnoreCase(event, \"SC_EVENT \")) {\n  char* args = event + 9;\n  trimAsciiInPlace(args);  // Only trim whitespace\n  // Splits on space without validating allowed characters\n}",
      "attack_scenario": "Send via serial: 'SC_EVENT serial '; DROP TABLE stories; --'\nResult: Injected event name contains semicolon and SQL-like syntax",
      "current_mitigation": "Limited to uppercase ASCII conversion, snprintf with size bounds",
      "impact": "Potential for scenario injection, unexpected state transitions",
      "remediation_steps": [
        "Implement strict character whitelist (alphanumeric, underscore only)",
        "Use regex validation for event names: ^[A-Z0-9_]+$",
        "Add length limits to event names (max 64 chars)",
        "Log all command parsing failures for monitoring"
      ]
    },
    {
      "id": "MED-002",
      "title": "Missing Input Bounds in Media Playback",
      "severity": "MEDIUM",
      "category": "Input Validation",
      "cwe": "CWE-400: Uncontrolled Resource Consumption",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [1815, 1820, 1875],
        "function": "dispatchControlAction() - MEDIA_PLAY, REC_START handlers"
      },
      "description": "User can supply arbitrary file paths for media playback and recording. No validation of path contents or file sizes. Could lead to resource exhaustion or information disclosure.",
      "attack_vector": "POST: 'MEDIA_PLAY /sdcard/../../etc/passwd'\nPOST: 'REC_START 99999999 /sdcard/../../../dangerous.wav'",
      "impact": "File traversal, information disclosure, resource exhaustion (filling storage)",
      "remediation_steps": [
        "Implement path whitelist (only allow /music/, /recorder/)",
        "Validate file existence before playback",
        "Add file size limits for recordings",
        "Enforce write-only access to recording directory"
      ]
    },
    {
      "id": "MED-003",
      "title": "No Rate Limiting on Web Endpoints",
      "severity": "MEDIUM",
      "category": "Denial of Service",
      "cwe": "CWE-770: Allocation of Resources Without Limits or Throttling",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [2007, 3366],
        "function": "Web request handlers, handleClient() loop"
      },
      "description": "Web endpoints have no rate limiting mechanism. Attacker can flood device with requests causing DoS or resource exhaustion.",
      "attack_scenario": "1. Send 1000 requests/sec to /api/status\n2. Device CPU maxes out parsing JSON\n3. Legitimate clients cannot connect\n4. Memory exhaustion from buffered responses",
      "impact": "Denial of Service, device unavailability",
      "remediation_steps": [
        "Implement per-IP rate limiting (e.g., 10 req/sec)",
        "Add request throttling in WebServer handler",
        "Implement exponential backoff for blocked IPs",
        "Add memory pooling for response buffers",
        "Implement request queue with maximum size"
      ]
    },
    {
      "id": "MED-004",
      "title": "Missing HTTPS/TLS for Web Communication",
      "severity": "MEDIUM",
      "category": "Encryption & Transport",
      "cwe": "CWE-295: Improper Certificate Validation",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [46],
        "definition": "WebServer g_web_server(80);"
      },
      "description": "WebServer operates on plain HTTP without encryption. All credentials, commands, and sensor data are transmitted in cleartext.",
      "attack_scenario": "Attacker on local WiFi:\n1. Packet sniff HTTP traffic\n2. Capture WiFi credentials from /api/network/wifi responses\n3. Read camera snapshots from network traffic\n4. Inject commands via MITM attack",
      "impact": "Complete information disclosure, credential theft, command injection via MITM",
      "remediation_steps": [
        "Implement HTTPS server using mbedTLS",
        "Generate self-signed certificate on first boot",
        "Use certificate pinning on client side",
        "Enforce HSTS header",
        "Disable HTTP completely"
      ]
    },
    {
      "id": "LOW-001",
      "title": "Missing Stack Canaries and Security Hardening",
      "severity": "LOW",
      "category": "Memory Protection",
      "cwe": "CWE-674: Uncontrolled Recursion",
      "location": {
        "file": "platformio.ini",
        "lines": [97, 98],
        "section": "build_flags"
      },
      "description": "Compiler flags do not include traditional stack protection mechanisms. ESP32 hardware SoC provides some mitigations but explicit protections are absent.",
      "current_flags": "-O2 -ffast-math\n(no -fstack-protector, -fPIE, -fPIC flags)",
      "notes": "ESP32 has hardware features (XTS-AES, secure boot) but they are not explicitly enabled in build configuration",
      "impact": "Slightly increased risk of buffer overflow exploitation (mitigated by bounded string functions used throughout)",
      "recommendations": [
        "Add -fstack-protector-strong to build flags",
        "Enable secure boot in partitions configuration",
        "Use -Wformat -Wformat-security for format string protection",
        "Consider CFI (Control Flow Integrity) with -fcf-protection=full"
      ]
    },
    {
      "id": "LOW-002", 
      "title": "Verbose Debug Output to Serial",
      "severity": "LOW",
      "category": "Information Disclosure",
      "cwe": "CWE-532: Insertion of Sensitive Information into Log File",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [920, 930, 1000, 1070],
        "functions": "printNetworkStatus(), printEspNowStatusJson(), printHardwareStatus()"
      },
      "description": "Debug output via Serial.printf() includes network configuration, WiFi SSID, ESP-NOW peers, and hardware status. Physical UART access could reveal device state.",
      "example_output": "Serial.printf(\"NET_STATUS... sta_ssid=%s ap_ssid=%s...\", net.sta_ssid, net.ap_ssid);",
      "attack_vector": "Physical access to UART pins during development/production",
      "impact": "Information disclosure of network topology, device capabilities",
      "mitigation": "Production builds already set CORE_DEBUG_LEVEL=0, Serial output is informational and expected behavior"
    },
    {
      "id": "LOW-003",
      "title": "Missing Input Sanitization in Event Names",
      "severity": "LOW",
      "category": "Input Validation",
      "cwe": "CWE-20: Improper Input Validation",
      "location": {
        "file": "ui_freenove_allinone/src/main.cpp",
        "lines": [355-380],
        "function": "extractEventTokenFromJsonObject()"
      },
      "description": "Event names extracted from JSON are not validated for content. While parsing is safe due to fixed-size buffers, special characters could cause unexpected behavior.",
      "impact": "Low - fixed buffer sizes and string handling prevent overflow, but invalid events could cause confusing state transitions",
      "recommendation": "Add whitelist validation for event name characters"
    }
  ],
  "recommendations_by_priority": {
    "immediate": [
      {
        "action": "Remove hardcoded WiFi credentials immediately",
        "target": "CRIT-001",
        "effort": "Medium",
        "timeline": "Before next release"
      },
      {
        "action": "Implement authentication on all Web API endpoints",
        "target": "CRIT-002",
        "effort": "High",
        "timeline": "Critical fix, delay deployment"
      },
      {
        "action": "Enable HTTPS for web communication",
        "target": "MED-004",
        "effort": "High",
        "timeline": "Before production deployment"
      }
    ],
    "short_term": [
      {
        "action": "Implement path traversal protection",
        "target": "HIGH-003",
        "effort": "Low",
        "timeline": "Next sprint"
      },
      {
        "action": "Add rate limiting to web endpoints",
        "target": "MED-003",
        "effort": "Medium",
        "timeline": "Next sprint"
      },
      {
        "action": "Add JSON schema validation",
        "target": "HIGH-002",
        "effort": "Low",
        "timeline": "Next sprint"
      }
    ],
    "long_term": [
      {
        "action": "Enable security hardening compiler flags",
        "target": "LOW-001",
        "effort": "Low",
        "timeline": "Next release cycle"
      },
      {
        "action": "Implement comprehensive input validation framework",
        "target": "MED-001, MED-002",
        "effort": "Medium",
        "timeline": "Architecture review"
      }
    ]
  },
  "compliance_considerations": {
    "fcc_emc": {
      "status": "Not directly evaluated in this security audit",
      "note": "ESP32-S3 is FCC certified for RF emissions. Ensure WiFi channels and TX power comply with regional regulations."
    },
    "gdpr": {
      "assessment": "Camera snapshot and audio recording capabilities touch on GDPR (data collection)",
      "recommendations": [
        "Implement user consent for camera/audio recording",
        "Add data retention policies and deletion mechanisms",
        "Provide audit logs for data access requests"
      ]
    },
    "product_safety": {
      "assessment": "Device is embedded system for children (based on /data/apps/kids_* directories)",
      "recommendations": [
        "Implement parental controls mechanism",
        "Restrict access to sensitive features during child mode",
        "Add activity logging for parent review",
        "Regular security updates for device"
      ]
    }
  },
  "cves_and_known_issues": {
    "esp32_issues": [
      {
        "topic": "ESP32 UART Download Mode",
        "risk": "MEDIUM",
        "mitigation": "Disable JTAG/UART access in production via eFuses"
      },
      {
        "topic": "WiFi WPA2 KRACK",
        "risk": "LOW",
        "note": "Mitigated by ESP-IDF firmware updates"
      }
    ]
  },
  "testing_recommendations": {
    "security_testing": [
      "Penetration test web endpoints with Burp Suite",
      "Firmware reverse engineering to identify additional hardcoded secrets",
      "Fuzz testing of JSON parsing with AFL or libFuzzer",
      "Path traversal testing with common payloads",
      "Rate limiting testing with ApacheBench/wrk"
    ],
    "unit_tests_needed": [
      "Input validation for all numeric parameters",
      "Path sanitization test cases",
      "JSON schema validation tests",
      "Authentication bypass attempts"
    ]
  },
  "audit_conclusion": {
    "overall_assessment": "The ESP32_ZACUS firmware contains multiple critical security vulnerabilities that must be addressed before production deployment. The most severe issues are the presence of hardcoded WiFi credentials and the complete absence of authentication on web API endpoints. While many input handling patterns are relatively safe due to bounded string operations, the lack of authentication is a critical control gap.",
    "deployment_readiness": "NOT READY FOR PRODUCTION",
    "estimated_remediation_time": "2-3 weeks for critical fixes, full hardening 4-6 weeks",
    "next_steps": [
      "Brief development team on findings",
      "Prioritize critical vulnerabilities (CRIT-001, CRIT-002)",
      "Implement secure credential storage using NVS",
      "Add authentication framework to web API",
      "Conduct security code review after fixes",
      "Re-run this audit after remediation"
    ]
  },
  "audit_sign_off": {
    "auditor": "Security Expert - Embedded Systems",
    "date": "2026-03-01",
    "scope": "Static analysis + source code review",
    "methodology": "CWE-based vulnerability classification, OWASP embedded security guidelines"
  }
}
