Audit Logging

interface AuditLogEvent {
  eventId: string
  timestamp: Date
  eventType: AuditEventType
  userId?: string
  sessionId?: string
  ipAddress: string
  userAgent?: string
  resource: string
  action: string
  outcome: 'success' | 'failure' | 'pending'
  riskLevel: 'low' | 'medium' | 'high' | 'critical'
  metadata: Record<string, any>
  contextData: ContextualData
}
 
interface ContextualData {
  geolocation?: GeolocationData
  deviceInfo?: DeviceFingerprint
  applicationContext?: ApplicationContext
  businessContext?: BusinessContext
}
 
enum AuditEventType {
  AUTHENTICATION = 'authentication',
  AUTHORIZATION = 'authorization',
  DATA_ACCESS = 'data_access',
  CONFIGURATION_CHANGE = 'config_change',
  SYSTEM_EVENT = 'system_event',
  SECURITY_EVENT = 'security_event',
  COMPLIANCE_EVENT = 'compliance_event',
  FINANCIAL_TRANSACTION = 'financial_transaction'
}

interface AuthenticationLog extends AuditLogEvent {
  eventType: AuditEventType.AUTHENTICATION
  authMethod: 'password' | 'mfa' | 'sso' | 'api_key' | 'certificate'
  authResult: 'success' | 'failure' | 'locked' | 'expired'
  failureReason?: string
  mfaMethod?: 'totp' | 'sms' | 'email' | 'hardware_token'
  previousLoginTime?: Date
  deviceTrust?: 'trusted' | 'untrusted' | 'new'
}
 
interface AuthorizationLog extends AuditLogEvent {
  eventType: AuditEventType.AUTHORIZATION
  requestedResource: string
  requestedAction: string
  permissions: string[]
  roleContext: string[]
  authorizationResult: 'granted' | 'denied' | 'escalated'
  policyEvaluated: string[]
}

interface DataAccessLog extends AuditLogEvent {
  eventType: AuditEventType.DATA_ACCESS
  dataType: 'customer_data' | 'financial_data' | 'pii' | 'system_config' | 'audit_log'
  dataClassification: 'public' | 'internal' | 'confidential' | 'restricted'
  accessMethod: 'read' | 'write' | 'delete' | 'export' | 'import'
  recordCount?: number
  dataRetentionPolicy?: string
  encryptionStatus: boolean
  backupStatus?: boolean
}
 
class AuditLogger {
  private logStore: LogStore
  private encryptionService: EncryptionService
 
  async logDataAccess(event: DataAccessEvent): Promise<void> {
    const auditLog: DataAccessLog = {
      eventId: this.generateEventId(),
      timestamp: new Date(),
      eventType: AuditEventType.DATA_ACCESS,
      userId: event.userId,
      sessionId: event.sessionId,
      ipAddress: event.ipAddress,
      resource: event.resource,
      action: event.action,
      outcome: event.outcome,
      riskLevel: this.calculateRiskLevel(event),
      dataType: event.dataType,
      dataClassification: event.dataClassification,
      accessMethod: event.accessMethod,
      recordCount: event.recordCount,
      encryptionStatus: event.encryptionStatus,
      metadata: this.enrichMetadata(event),
      contextData: await this.gatherContext(event)
    }
 
    // Encrypt sensitive log data
    const encryptedLog = await this.encryptionService.encryptAuditLog(auditLog)
 
    // Store with integrity protection
    await this.logStore.storeWithIntegrity(encryptedLog)
 
    // Real-time security analysis
    if (auditLog.riskLevel === 'critical' || auditLog.riskLevel === 'high') {
      await this.triggerSecurityAlert(auditLog)
    }
  }
}

configuration_logging:
  tracked_changes:
    - system_configurations
    - security_policies
    - user_permissions
    - network_configurations
    - encryption_settings
    - backup_configurations
    - monitoring_rules
    - compliance_settings
 
  change_attributes:
    - change_type: "create|update|delete|restore"
    - old_value: "previous_configuration"
    - new_value: "updated_configuration"
    - change_reason: "business_justification"
    - approval_reference: "change_request_id"
    - rollback_capability: boolean
 
  notification_triggers:
    critical_changes:
      - security_policy_modifications
      - admin_privilege_changes
      - encryption_key_rotations
      - compliance_setting_updates
 
    recipients:
      - security_team
      - compliance_team
      - system_administrators

interface SystemEventLog extends AuditLogEvent {
  eventType: AuditEventType.SYSTEM_EVENT
  systemComponent: string
  eventCategory: 'startup' | 'shutdown' | 'error' | 'warning' | 'performance'
  severity: 'info' | 'warning' | 'error' | 'critical'
  errorCode?: string
  stackTrace?: string
  performanceMetrics?: PerformanceMetrics
  systemHealth: SystemHealthStatus
}
 
interface PerformanceMetrics {
  cpuUsage: number
  memoryUsage: number
  diskUsage: number
  networkLatency: number
  responseTime: number
  throughput: number
}

interface SecurityEventLog extends AuditLogEvent {
  eventType: AuditEventType.SECURITY_EVENT
  securityEventType: SecurityEventType
  threatIndicators: ThreatIndicator[]
  attackVector?: string
  mitigationActions: MitigationAction[]
  forensicData: ForensicData
  incidentSeverity: 'low' | 'medium' | 'high' | 'critical'
  responseTime: number
}
 
enum SecurityEventType {
  FAILED_AUTHENTICATION = 'failed_authentication',
  PRIVILEGE_ESCALATION = 'privilege_escalation',
  SUSPICIOUS_ACTIVITY = 'suspicious_activity',
  MALWARE_DETECTION = 'malware_detection',
  DATA_EXFILTRATION = 'data_exfiltration',
  VULNERABILITY_EXPLOITATION = 'vulnerability_exploitation',
  POLICY_VIOLATION = 'policy_violation',
  INTRUSION_ATTEMPT = 'intrusion_attempt'
}
 
class SecurityEventLogger {
  async logSecurityEvent(event: SecurityEvent): Promise<void> {
    const securityLog: SecurityEventLog = {
      eventId: this.generateSecurityEventId(),
      timestamp: new Date(),
      eventType: AuditEventType.SECURITY_EVENT,
      securityEventType: event.type,
      userId: event.userId,
      ipAddress: event.ipAddress,
      resource: event.resource,
      action: event.action,
      outcome: event.outcome,
      riskLevel: 'critical',
      threatIndicators: event.threatIndicators,
      attackVector: event.attackVector,
      mitigationActions: await this.getActiveMitigations(event),
      forensicData: await this.collectForensicData(event),
      incidentSeverity: this.calculateIncidentSeverity(event),
      responseTime: this.calculateResponseTime(event),
      metadata: event.metadata,
      contextData: await this.gatherSecurityContext(event)
    }
 
    // Immediate storage with high priority
    await this.storeSecurityLog(securityLog)
 
    // Trigger automated response
    await this.triggerSecurityResponse(securityLog)
 
    // Notify security team
    await this.notifySecurityTeam(securityLog)
  }
}

log_retention_policy:
  authentication_logs:
    hot_storage: "30_days"
    warm_storage: "1_year"
    cold_storage: "7_years"
    archive_storage: "indefinite"
 
  data_access_logs:
    hot_storage: "90_days"
    warm_storage: "2_years"
    cold_storage: "7_years"
    archive_storage: "indefinite"
 
  security_logs:
    hot_storage: "90_days"
    warm_storage: "3_years"
    cold_storage: "10_years"
    archive_storage: "indefinite"
 
  system_logs:
    hot_storage: "30_days"
    warm_storage: "1_year"
    cold_storage: "3_years"
    archive_storage: "7_years"
 
  compliance_logs:
    hot_storage: "1_year"
    warm_storage: "3_years"
    cold_storage: "10_years"
    archive_storage: "indefinite"
 
  storage_encryption:
    at_rest: true
    in_transit: true
    key_rotation: "quarterly"
    backup_encryption: true

class LogAnalysisEngine {
  private mlModels: MachineLearningModels
  private ruleEngine: SecurityRuleEngine
  private correlationEngine: EventCorrelationEngine
 
  async analyzeLogStream(logs: AuditLogEvent[]): Promise<AnalysisResult[]> {
    const results: AnalysisResult[] = []
 
    // Real-time rule-based analysis
    for (const log of logs) {
      const ruleResults = await this.ruleEngine.evaluate(log)
      if (ruleResults.triggered) {
        results.push({
          type: 'rule_violation',
          severity: ruleResults.severity,
          description: ruleResults.description,
          recommendations: ruleResults.recommendations
        })
      }
    }
 
    // Machine learning anomaly detection
    const anomalies = await this.mlModels.detectAnomalies(logs)
    results.push(...anomalies)
 
    // Event correlation analysis
    const correlations = await this.correlationEngine.correlateLogs(logs)
    results.push(...correlations)
 
    // Generate alerts for high-priority findings
    await this.generateAlerts(results.filter(r => r.severity === 'high' || r.severity === 'critical'))
 
    return results
  }
 
  async generateComplianceReport(period: DateRange): Promise<ComplianceReport> {
    const logs = await this.retrieveLogsByPeriod(period)
 
    return {
      period,
      totalEvents: logs.length,
      authenticationEvents: logs.filter(l => l.eventType === AuditEventType.AUTHENTICATION).length,
      dataAccessEvents: logs.filter(l => l.eventType === AuditEventType.DATA_ACCESS).length,
      securityEvents: logs.filter(l => l.eventType === AuditEventType.SECURITY_EVENT).length,
      failedAttempts: logs.filter(l => l.outcome === 'failure').length,
      privilegedAccess: this.countPrivilegedAccess(logs),
      policyViolations: this.countPolicyViolations(logs),
      complianceScore: this.calculateComplianceScore(logs)
    }
  }
}

class LogIntegrityManager {
  private hashChain: HashChain
  private digitalSignature: DigitalSignatureService
  private timestampService: TimestampService
 
  async protectLogIntegrity(log: AuditLogEvent): Promise<ProtectedLog> {
    // Generate cryptographic hash
    const logHash = await this.generateLogHash(log)
 
    // Add to hash chain for tamper detection
    const chainEntry = await this.hashChain.addEntry(logHash)
 
    // Digital signature for non-repudiation
    const signature = await this.digitalSignature.sign(log, logHash)
 
    // Trusted timestamp
    const timestamp = await this.timestampService.timestamp(logHash)
 
    return {
      originalLog: log,
      hash: logHash,
      chainPosition: chainEntry.position,
      previousHash: chainEntry.previousHash,
      signature: signature,
      timestamp: timestamp,
      integrity: 'protected'
    }
  }
 
  async verifyLogIntegrity(protectedLog: ProtectedLog): Promise<IntegrityResult> {
    // Verify hash
    const computedHash = await this.generateLogHash(protectedLog.originalLog)
    const hashValid = computedHash === protectedLog.hash
 
    // Verify chain integrity
    const chainValid = await this.hashChain.verifyChain(protectedLog.chainPosition)
 
    // Verify digital signature
    const signatureValid = await this.digitalSignature.verify(
      protectedLog.originalLog,
      protectedLog.signature
    )
 
    // Verify timestamp
    const timestampValid = await this.timestampService.verify(protectedLog.timestamp)
 
    return {
      overall: hashValid && chainValid && signatureValid && timestampValid,
      hashIntegrity: hashValid,
      chainIntegrity: chainValid,
      signatureIntegrity: signatureValid,
      timestampIntegrity: timestampValid
    }
  }
}

soc2_logging_requirements:
  security_principle:
    user_authentication: "log_all_attempts"
    authorization_decisions: "log_all_decisions"
    system_access: "log_privileged_access"
    configuration_changes: "log_all_changes"
 
  availability_principle:
    system_monitoring: "continuous_logging"
    performance_metrics: "log_performance_data"
    capacity_management: "log_resource_usage"
    backup_operations: "log_backup_activities"
 
  processing_integrity:
    data_validation: "log_validation_results"
    error_handling: "log_all_errors"
    data_transformation: "log_processing_steps"
    transaction_processing: "log_financial_transactions"
 
  confidentiality_principle:
    data_encryption: "log_encryption_operations"
    data_classification: "log_classification_decisions"
    access_restrictions: "log_confidential_access"
    data_transmission: "log_secure_transmissions"
 
  privacy_principle:
    personal_data_access: "log_pii_access"
    consent_management: "log_consent_changes"
    data_retention: "log_retention_actions"
    data_deletion: "log_deletion_activities"

class ComplianceReportGenerator {
  async generateSOC2Report(period: DateRange): Promise<SOC2ComplianceReport> {
    const logs = await this.getComplianceLogs(period)
 
    return {
      reportPeriod: period,
      securityControls: {
        userAuthentication: this.analyzeAuthenticationLogs(logs),
        systemAccess: this.analyzeAccessLogs(logs),
        configurationManagement: this.analyzeConfigLogs(logs),
        logicalSecurity: this.analyzeSecurityLogs(logs)
      },
      availabilityControls: {
        systemMonitoring: this.analyzeMonitoringLogs(logs),
        changeManagement: this.analyzeChangeLogs(logs),
        backupRecovery: this.analyzeBackupLogs(logs)
      },
      processingIntegrityControls: {
        dataValidation: this.analyzeValidationLogs(logs),
        errorHandling: this.analyzeErrorLogs(logs),
        transactionProcessing: this.analyzeTransactionLogs(logs)
      },
      confidentialityControls: {
        dataEncryption: this.analyzeEncryptionLogs(logs),
        accessRestrictions: this.analyzeAccessRestrictionLogs(logs)
      },
      privacyControls: {
        personalDataHandling: this.analyzePIILogs(logs),
        consentManagement: this.analyzeConsentLogs(logs),
        dataRetention: this.analyzeRetentionLogs(logs)
      },
      exceptions: this.identifyExceptions(logs),
      recommendations: this.generateRecommendations(logs)
    }
  }
}

interface AuditLogAPI {
  // Log creation
  createLog(event: AuditLogEvent): Promise<string>
  batchCreateLogs(events: AuditLogEvent[]): Promise<string[]>
 
  // Log retrieval
  getLogs(filter: LogFilter): Promise<AuditLogEvent[]>
  getLogById(eventId: string): Promise<AuditLogEvent>
  searchLogs(query: SearchQuery): Promise<SearchResult>
 
  // Analytics
  getSecurityMetrics(period: DateRange): Promise<SecurityMetrics>
  getComplianceReport(type: ComplianceType, period: DateRange): Promise<ComplianceReport>
 
  // Administrative
  verifyLogIntegrity(eventId: string): Promise<IntegrityResult>
  exportLogs(filter: LogFilter, format: ExportFormat): Promise<ExportResult>
}

siem_integration:
  supported_formats:
    - syslog_rfc3164
    - syslog_rfc5424
    - json_over_tcp
    - splunk_hec
    - elasticsearch_bulk
    - kafka_streams
 
  real_time_streaming:
    protocol: "tcp_tls"
    compression: "gzip"
    batch_size: 1000
    flush_interval: "30_seconds"
    retry_policy: "exponential_backoff"
 
  field_mapping:
    timestamp: "@timestamp"
    severity: "level"
    user_id: "user.id"
    ip_address: "source.ip"
    event_type: "event.category"
    outcome: "event.outcome"