# WIA-SEC-017: Security Audit
## Phase 1 - Core Foundation

**Standard ID:** WIA-SEC-017
**Category:** Security (SEC)
**Version:** 1.0.0
**Status:** Active
**Last Updated:** 2025-12-25

---

## 1. Executive Summary

WIA-SEC-017 establishes a comprehensive security audit standard for maintaining detailed audit trails, compliance logging, and regulatory reporting. This standard provides a unified framework for capturing, storing, analyzing, and reporting security-relevant events across enterprise systems to meet requirements of SOC2, ISO27001, GDPR, HIPAA, PCI-DSS, and other compliance frameworks.

### Key Objectives

1. **Comprehensive Audit Trails** - Capture all security-relevant events systematically
2. **Compliance Support** - Built-in support for major regulatory frameworks
3. **Tamper-Proof Logging** - Cryptographic integrity protection for audit records
4. **Real-time Monitoring** - Continuous security event analysis and alerting
5. **Automated Reporting** - Generate compliance reports and evidence collections

---

## 2. Core Architecture

### 2.1 Audit System Components

The WIA-SEC-017 audit system consists of four primary components:

#### Audit Collector
- Captures events from all system components
- Normalizes event data to standard format
- Performs initial classification and tagging
- Buffers events for batch transmission

#### Audit Storage
- Immutable, tamper-proof log storage
- Blockchain-inspired chain structure
- Cryptographic signing and verification
- Long-term retention management

#### Audit Analyzer
- Real-time event analysis
- Anomaly detection using ML algorithms
- Pattern recognition and correlation
- Risk scoring and prioritization

#### Audit Reporter
- Compliance report generation
- Evidence collection and packaging
- Dashboard and visualization
- Alert and notification system

### 2.2 System Architecture Diagram

```
┌─────────────────────────────────────────────────────────┐
│                   Application Layer                      │
│   ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌────────┐ │
│   │   Web    │  │   API    │  │ Database │  │  Auth  │ │
│   │  Server  │  │  Server  │  │  Server  │  │ Server │ │
│   └────┬─────┘  └────┬─────┘  └────┬─────┘  └────┬───┘ │
└────────┼─────────────┼─────────────┼──────────────┼─────┘
         │             │             │              │
         └─────────────┴─────────────┴──────────────┘
                        │
              ┌─────────▼──────────┐
              │  Audit Collector   │
              │  - Event Capture   │
              │  - Normalization   │
              │  - Classification  │
              └─────────┬──────────┘
                        │
              ┌─────────▼──────────┐
              │   Audit Storage    │
              │  - Immutable Logs  │
              │  - Crypto Signing  │
              │  - Chain Structure │
              └─────────┬──────────┘
                        │
         ┌──────────────┼──────────────┐
         │              │              │
    ┌────▼─────┐  ┌─────▼─────┐  ┌────▼──────┐
    │ Analyzer │  │  Reporter │  │   SIEM    │
    │ - ML     │  │ - Reports │  │ Integration│
    │ - Detect │  │ - Alerts  │  │ - Splunk  │
    └──────────┘  └───────────┘  └───────────┘
```

---

## 3. Audit Event Data Model

### 3.1 Standard Audit Entry Structure

Every audit event follows this standardized structure:

```json
{
  "audit_id": "AUD-2025-12345678",
  "timestamp": "2025-12-25T10:30:45.123Z",
  "event_type": "AUTHENTICATION|AUTHORIZATION|DATA_ACCESS|CONFIGURATION_CHANGE|...",
  "severity": "INFO|LOW|MEDIUM|HIGH|CRITICAL",
  "actor": {
    "user_id": "string",
    "type": "HUMAN|SERVICE|SYSTEM",
    "ip_address": "string",
    "user_agent": "string",
    "session_id": "string",
    "location": {
      "country": "string",
      "region": "string",
      "city": "string",
      "coordinates": {"lat": 0.0, "lon": 0.0}
    }
  },
  "resource": {
    "type": "API_ENDPOINT|DATABASE|FILE|CONFIGURATION|...",
    "id": "string",
    "classification": "PUBLIC|INTERNAL|CONFIDENTIAL|RESTRICTED"
  },
  "action": {
    "operation": "CREATE|READ|UPDATE|DELETE|EXECUTE|...",
    "status": "SUCCESS|FAILURE|PARTIAL",
    "duration_ms": 0,
    "result": "string"
  },
  "metadata": {
    "compliance_tags": ["SOC2", "ISO27001", "GDPR", "HIPAA", "PCI-DSS"],
    "data_classification": "PII|PHI|PCI|SECRET|...",
    "retention_days": 2555,
    "custom_fields": {}
  },
  "cryptographic_proof": {
    "hash": "sha256:...",
    "signature": "RSA:...",
    "chain_link": "prev:...",
    "verification_key_id": "string"
  }
}
```

### 3.2 Event Type Classification

| Event Type | Description | Examples |
|------------|-------------|----------|
| AUTHENTICATION | User/service authentication attempts | Login, logout, MFA, SSO |
| AUTHORIZATION | Permission checks and access control | Role assignment, permission grant/revoke |
| DATA_ACCESS | Access to sensitive data | Database query, file read, API call |
| DATA_MODIFICATION | Changes to data | Create, update, delete operations |
| CONFIGURATION_CHANGE | System configuration changes | Settings update, policy modification |
| PRIVILEGE_ESCALATION | Elevation of permissions | Sudo, admin access grant |
| SECURITY_EVENT | Security-specific events | Firewall block, intrusion detection |
| COMPLIANCE_EVENT | Compliance-related activities | Policy violation, audit request |
| SYSTEM_EVENT | System-level operations | Startup, shutdown, backup |

### 3.3 Severity Levels

| Level | Score | Description | Response Time | Examples |
|-------|-------|-------------|---------------|----------|
| CRITICAL | 90-100 | Immediate security threat | < 5 minutes | Data breach, privilege escalation |
| HIGH | 70-89 | Significant security concern | < 1 hour | Failed admin login, policy violation |
| MEDIUM | 40-69 | Notable security event | < 24 hours | Unusual access pattern, config change |
| LOW | 20-39 | Minor security event | < 7 days | Normal access, routine operation |
| INFO | 0-19 | Informational only | As needed | Successful login, normal query |

---

## 4. Tamper-Proof Logging Mechanism

### 4.1 Blockchain-Inspired Chain Structure

Each audit log entry is cryptographically linked to the previous entry, creating an immutable chain:

```
Block N-1                    Block N                      Block N+1
┌──────────────┐            ┌──────────────┐            ┌──────────────┐
│ Data         │            │ Data         │            │ Data         │
│ Timestamp    │            │ Timestamp    │            │ Timestamp    │
│ Hash: ABC123 │───────────▶│ Prev: ABC123 │───────────▶│ Prev: DEF456 │
│              │            │ Hash: DEF456 │            │ Hash: GHI789 │
│ Signature    │            │ Signature    │            │ Signature    │
└──────────────┘            └──────────────┘            └──────────────┘
```

### 4.2 Cryptographic Hash Calculation

```javascript
function calculateAuditHash(entry, previousHash) {
  const data = {
    audit_id: entry.audit_id,
    timestamp: entry.timestamp,
    event_type: entry.event_type,
    actor: entry.actor,
    resource: entry.resource,
    action: entry.action,
    previous_hash: previousHash
  };

  // SHA-256 hash of canonical JSON
  const canonical = JSON.stringify(sortKeys(data));
  return sha256(canonical);
}
```

### 4.3 Digital Signature

```javascript
function signAuditEntry(entry, privateKey) {
  const hash = calculateAuditHash(entry);

  // RSA-SHA256 signature
  const signature = crypto.sign(
    'sha256',
    Buffer.from(hash, 'hex'),
    {
      key: privateKey,
      padding: crypto.constants.RSA_PKCS1_PSS_PADDING
    }
  );

  return {
    ...entry,
    cryptographic_proof: {
      hash: hash,
      signature: signature.toString('base64'),
      algorithm: 'RSA-SHA256',
      key_id: getPublicKeyId(privateKey)
    }
  };
}
```

### 4.4 Chain Integrity Verification

```javascript
function verifyAuditChain(chain) {
  for (let i = 1; i < chain.length; i++) {
    const current = chain[i];
    const previous = chain[i - 1];

    // 1. Verify hash linkage
    if (current.cryptographic_proof.chain_link !== previous.cryptographic_proof.hash) {
      return {
        valid: false,
        error: `Chain broken at entry ${i}`,
        entry_id: current.audit_id
      };
    }

    // 2. Verify digital signature
    const publicKey = getPublicKey(current.cryptographic_proof.verification_key_id);
    const isValid = crypto.verify(
      'sha256',
      Buffer.from(current.cryptographic_proof.hash, 'hex'),
      publicKey,
      Buffer.from(current.cryptographic_proof.signature, 'base64')
    );

    if (!isValid) {
      return {
        valid: false,
        error: `Invalid signature at entry ${i}`,
        entry_id: current.audit_id
      };
    }

    // 3. Verify timestamp ordering
    if (new Date(current.timestamp) < new Date(previous.timestamp)) {
      return {
        valid: false,
        error: `Timestamp violation at entry ${i}`,
        entry_id: current.audit_id
      };
    }
  }

  return {
    valid: true,
    entries_verified: chain.length,
    first_entry: chain[0].audit_id,
    last_entry: chain[chain.length - 1].audit_id
  };
}
```

---

## 5. Compliance Framework Mapping

### 5.1 SOC 2 Type II Requirements

| Control | WIA-SEC-017 Implementation |
|---------|---------------------------|
| CC6.1 - Security Event Monitoring | Real-time audit collection and analysis |
| CC6.2 - Change Management | Configuration change audit trail |
| CC6.3 - Access Monitoring | Authentication and authorization logging |
| CC7.1 - Detection of Security Events | Anomaly detection and alerting |
| CC7.2 - Response to Security Incidents | Automated incident response triggers |

### 5.2 ISO/IEC 27001:2022 Requirements

| Control | Description | Implementation |
|---------|-------------|----------------|
| A.12.4.1 | Event logging | Comprehensive event capture |
| A.12.4.2 | Protection of log information | Cryptographic integrity protection |
| A.12.4.3 | Administrator and operator logs | Privileged user activity tracking |
| A.12.4.4 | Clock synchronization | NTP-synchronized timestamps |
| A.18.1.5 | Regulation of cryptographic controls | Cryptographic key management |

### 5.3 GDPR Compliance

| Requirement | Article | Implementation |
|-------------|---------|----------------|
| Records of processing activities | Art. 30 | Comprehensive audit trails |
| Security of processing | Art. 32 | Tamper-proof logging |
| Notification of personal data breach | Art. 33 | Real-time breach detection |
| Rights of data subjects | Art. 15-22 | Data access audit logging |

### 5.4 HIPAA Requirements

| Requirement | Section | Implementation |
|-------------|---------|----------------|
| Audit controls | §164.312(b) | Complete audit trail system |
| Access establishment and modification | §164.308(a)(4) | Authorization change logging |
| Log-in monitoring | §164.308(a)(5)(ii)(C) | Authentication event tracking |
| Protection from malicious software | §164.308(a)(5)(ii)(B) | Security event detection |

### 5.5 PCI-DSS Requirements

| Requirement | Description | Implementation |
|-------------|-------------|----------------|
| 10.1 | Link users to actions | Actor identification in all logs |
| 10.2 | Audit trail for system components | Comprehensive event logging |
| 10.3 | Record audit trail entries | Standard audit entry format |
| 10.5 | Secure audit trails | Tamper-proof logging mechanism |
| 10.6 | Review logs and security events | Real-time analysis and alerting |

---

## 6. Retention and Lifecycle Management

### 6.1 Retention Policies

| Compliance Framework | Minimum Retention | Recommended Retention |
|---------------------|-------------------|----------------------|
| SOC 2 | 1 year | 7 years |
| ISO 27001 | No specific requirement | 3-7 years |
| GDPR | As necessary | 3 years (with exceptions) |
| HIPAA | 6 years | 7 years |
| PCI-DSS | 1 year (3 months online) | 7 years |

### 6.2 Lifecycle States

```
┌─────────┐    ┌─────────┐    ┌──────────┐    ┌─────────┐    ┌──────────┐
│  ACTIVE │───▶│  WARM   │───▶│   COLD   │───▶│ ARCHIVE │───▶│ DELETED  │
└─────────┘    └─────────┘    └──────────┘    └─────────┘    └──────────┘
  0-90 days    90-365 days    1-3 years       3-7 years       After 7 years

  Hot Storage   Warm Storage  Cold Storage    Archive         Secure
  (SSD/RAM)     (SSD)         (HDD/Object)    (Tape/Glacier)  Deletion
```

### 6.3 Data Archival Process

```javascript
async function archiveAuditLogs(startDate, endDate) {
  // 1. Query logs for archival period
  const logs = await queryAuditLogs({
    timestamp_gte: startDate,
    timestamp_lte: endDate,
    state: 'COLD'
  });

  // 2. Verify chain integrity
  const verification = verifyAuditChain(logs);
  if (!verification.valid) {
    throw new Error('Chain integrity violation before archival');
  }

  // 3. Create archive package
  const archive = {
    archive_id: generateArchiveId(),
    period: { start: startDate, end: endDate },
    entry_count: logs.length,
    logs: logs,
    integrity_proof: verification,
    created_at: new Date().toISOString()
  };

  // 4. Compress and encrypt
  const compressed = await compress(archive, 'gzip');
  const encrypted = await encrypt(compressed, archiveEncryptionKey);

  // 5. Store to archive storage (Glacier, tape, etc.)
  await storeToArchive(encrypted, {
    storage_class: 'GLACIER_DEEP_ARCHIVE',
    retention_years: 7
  });

  // 6. Create retrieval metadata
  await createArchiveMetadata({
    archive_id: archive.archive_id,
    period: archive.period,
    entry_count: archive.entry_count,
    storage_location: 's3://archives/...',
    retrieval_time_hours: 48
  });

  // 7. Mark original logs as archived
  await updateLogState(logs, 'ARCHIVED');

  return archive.archive_id;
}
```

---

## 7. API Specifications

### 7.1 Submit Audit Event

```
POST /api/v1/audit/submit
Content-Type: application/json
Authorization: Bearer {token}
X-Audit-Signature: {signature}
X-Audit-Timestamp: {timestamp}
X-Audit-Nonce: {nonce}

Request Body: Standard Audit Entry (see Section 3.1)

Response (201 Created):
{
  "status": "ACCEPTED",
  "receipt_id": "RCPT-2025-98765432",
  "timestamp": "2025-12-25T10:30:45.456Z",
  "audit_id": "AUD-2025-12345678",
  "compliance_verification": {
    "soc2": true,
    "iso27001": true,
    "gdpr": true,
    "hipaa": true,
    "pci_dss": true
  },
  "retention_expires": "2032-12-25T10:30:45.456Z",
  "chain_position": 123456
}
```

### 7.2 Query Audit Logs

```
GET /api/v1/audit/query?start_date={date}&end_date={date}&event_type={type}
Authorization: Bearer {token}

Response (200 OK):
{
  "total_count": 1523,
  "page": 1,
  "page_size": 100,
  "results": [
    {Standard Audit Entry},
    ...
  ],
  "integrity_verified": true
}
```

### 7.3 Verify Audit Chain

```
POST /api/v1/audit/verify
Content-Type: application/json
Authorization: Bearer {token}

Request:
{
  "start_audit_id": "AUD-2025-12345678",
  "end_audit_id": "AUD-2025-12345999"
}

Response (200 OK):
{
  "valid": true,
  "entries_verified": 322,
  "first_entry": {
    "audit_id": "AUD-2025-12345678",
    "timestamp": "2025-12-25T10:30:45.123Z"
  },
  "last_entry": {
    "audit_id": "AUD-2025-12345999",
    "timestamp": "2025-12-25T12:15:30.789Z"
  },
  "verification_timestamp": "2025-12-25T13:00:00.000Z"
}
```

---

## 8. Security Considerations

### 8.1 Access Control

- Audit logs are **write-once, read-many** (WORM)
- Only authorized audit administrators can query logs
- Separation of duties: log writers ≠ log readers
- Multi-factor authentication required for audit access
- All access to audit logs is itself audited

### 8.2 Encryption

- **In-transit**: TLS 1.3 for all API communications
- **At-rest**: AES-256-GCM for stored audit logs
- **Archive**: AES-256-GCM + additional layer for long-term storage
- Key rotation: Every 90 days minimum

### 8.3 Key Management

- HSM (Hardware Security Module) for signing keys
- Separate key hierarchy: master key → audit key → log keys
- Multi-party key ceremony for master key generation
- Key escrow for disaster recovery

---

## 9. Performance Requirements

### 9.1 Throughput

- Minimum: 10,000 audit events per second
- Target: 100,000 audit events per second
- Peak: 1,000,000 audit events per second (burst)

### 9.2 Latency

- Event submission: < 10ms (p99)
- Query response: < 100ms for recent data (p95)
- Integrity verification: < 1s for 10,000 entries

### 9.3 Availability

- Service uptime: 99.99% (52 minutes downtime/year)
- Data durability: 99.999999999% (11 nines)
- Regional redundancy: Multi-region active-active

---

## 10. Implementation Checklist

- [ ] Deploy audit collection infrastructure
- [ ] Configure event sources and integrations
- [ ] Set up tamper-proof storage with cryptographic signing
- [ ] Implement audit chain verification
- [ ] Configure retention policies per compliance requirements
- [ ] Set up real-time monitoring and alerting
- [ ] Integrate with SIEM systems
- [ ] Configure compliance reporting
- [ ] Conduct security audit of audit system
- [ ] Train staff on audit system usage
- [ ] Establish incident response procedures
- [ ] Schedule regular integrity verification
- [ ] Plan disaster recovery and backup procedures

---

**Next Phase:** [PHASE-2-&-3-&-4.md](./PHASE-2-&-3-&-4.md) - Advanced Implementation

---

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