# WIA-SEC-005: Zero Trust Architecture
## Phase 1 - Foundation

**Standard ID:** WIA-SEC-005
**Category:** Security (SEC)
**Version:** 1.0.0
**Status:** Active
**Last Updated:** 2025-12-25

---

## 1. Executive Summary

WIA-SEC-005 establishes a comprehensive Zero Trust Architecture standard based on the foundational principle "Never Trust, Always Verify." This standard eliminates the concept of implicit trust based on network location and instead requires continuous verification of every user, device, and transaction attempting to access resources.

### Key Principles

1. **Never Trust, Always Verify** - No implicit trust regardless of location
2. **Least Privilege Access** - Minimum necessary permissions
3. **Microsegmentation** - Isolated network zones
4. **Continuous Verification** - Ongoing validation throughout session
5. **Device Trust** - Security posture assessment before access
6. **Assume Breach** - Design as if attackers are already inside

---

## 2. Core Architecture

### 2.1 Zero Trust Control Plane

The Zero Trust Control Plane consists of three primary components based on NIST SP 800-207:

#### Policy Decision Point (PDP)
- Evaluates access requests against policies
- Calculates trust scores
- Makes allow/deny/step-up decisions
- Interfaces with external systems (IAM, threat intelligence, etc.)

#### Policy Enforcement Point (PEP)
- Enforces decisions from PDP
- Terminates, forwards, or drops traffic
- Establishes and maintains sessions
- Monitors active sessions

#### Policy Administration Point (PAP)
- Manages policy lifecycle
- Defines access rules
- Configures trust scoring parameters
- Maintains policy repository

### 2.2 Trust Engine Components

```
┌──────────────────────────────────────────────────────┐
│              Zero Trust Policy Engine                 │
│                                                       │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐  │
│  │   Identity  │  │   Device    │  │  Behavior   │  │
│  │  Validator  │  │  Validator  │  │  Analyzer   │  │
│  └─────────────┘  └─────────────┘  └─────────────┘  │
│                                                       │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐  │
│  │   Context   │  │    Risk     │  │   Policy    │  │
│  │  Evaluator  │  │   Engine    │  │   Engine    │  │
│  └─────────────┘  └─────────────┘  └─────────────┘  │
└──────────────────────────────────────────────────────┘
```

---

## 3. Trust Scoring Model

### 3.1 Multi-Factor Trust Calculation

Trust score is calculated using weighted factors:

| Factor | Weight | Description |
|--------|--------|-------------|
| Identity Score | 30% | Authentication method strength, credential validity |
| Device Compliance | 25% | Security posture, patch level, encryption status |
| Behavior Score | 25% | Historical patterns, anomaly detection |
| Network Context | 20% | Location, IP reputation, network type |

### 3.2 Trust Score Formula

```
TrustScore = (
    IdentityScore × 0.30 +
    DeviceScore × 0.25 +
    BehaviorScore × 0.25 +
    NetworkScore × 0.20
) - RiskModifiers
```

### 3.3 Risk Modifiers

Risk factors that reduce trust score:

- **Unusual Location**: -15 points
- **Unusual Time**: -10 points
- **New/Unknown Device**: -20 points
- **Failed Authentication Attempts**: -5 points per failure
- **Known Threat Indicators**: -40 points

### 3.4 Trust Levels and Actions

| Trust Score | Level | Action |
|-------------|-------|--------|
| 85-100 | High | Full access granted |
| 70-84 | Medium | Limited access, enhanced monitoring |
| 50-69 | Low | Step-up authentication required |
| 0-49 | Critical | Access denied, alert triggered |

---

## 4. Identity Verification

### 4.1 Authentication Methods

Ranked by strength (highest to lowest):

1. **Biometric + Hardware Token** (Score: 100)
2. **FIDO2/WebAuthn** (Score: 95)
3. **Multi-Factor Authentication (MFA)** (Score: 90)
4. **Smart Card/PIV** (Score: 85)
5. **Time-based OTP (TOTP)** (Score: 80)
6. **SMS OTP** (Score: 60)
7. **Password Only** (Score: 40)

### 4.2 Identity Attributes

Required attributes for trust calculation:

```json
{
  "userId": "string",
  "authenticationMethod": "mfa|biometric|password|...",
  "authenticationTimestamp": "ISO-8601",
  "mfaVerified": boolean,
  "identityProvider": "string",
  "userGroups": ["string"],
  "roles": ["string"],
  "attributes": {
    "department": "string",
    "clearanceLevel": "string",
    "employeeStatus": "active|suspended|terminated"
  }
}
```

---

## 5. Device Trust

### 5.1 Device Compliance Requirements

Minimum compliance requirements:

#### Operating System
- Latest OS version or N-1
- Security updates applied within 30 days
- Automatic updates enabled

#### Security Features
- Full disk encryption enabled
- Anti-malware active and updated (< 24 hours)
- Firewall enabled
- Screen lock configured (< 15 minutes)

#### Device Management
- Device enrolled in MDM/UEM
- Device compliance policies enforced
- Remote wipe capability enabled

### 5.2 Device Posture Assessment

```json
{
  "deviceId": "string",
  "deviceType": "desktop|laptop|mobile|tablet",
  "operatingSystem": {
    "name": "string",
    "version": "string",
    "patchLevel": "string",
    "lastPatchDate": "ISO-8601"
  },
  "securityFeatures": {
    "encryptionEnabled": boolean,
    "antivirusActive": boolean,
    "antivirusLastUpdate": "ISO-8601",
    "firewallEnabled": boolean,
    "screenLockConfigured": boolean
  },
  "managementStatus": {
    "mdmEnrolled": boolean,
    "complianceStatus": "compliant|non-compliant",
    "jailbroken": boolean,
    "rooted": boolean
  },
  "healthScore": 0-100
}
```

---

## 6. Network Context Evaluation

### 6.1 Network Trust Factors

| Factor | High Trust | Medium Trust | Low Trust |
|--------|------------|--------------|-----------|
| Network Type | Corporate LAN | Corporate VPN | Public WiFi |
| IP Reputation | Clean (known corporate) | Unknown | Threat listed |
| Geographic Location | Expected region | Different region | High-risk country |
| VPN Status | Corporate VPN | Trusted VPN | No VPN |

### 6.2 Network Context Data

```json
{
  "sessionId": "string",
  "sourceIP": "string",
  "ipReputation": {
    "score": 0-100,
    "listed": boolean,
    "categories": ["spam", "malware", "proxy"]
  },
  "geolocation": {
    "country": "string",
    "region": "string",
    "city": "string",
    "coordinates": {
      "latitude": number,
      "longitude": number
    }
  },
  "networkType": "corporate-lan|corporate-vpn|public-wifi|mobile",
  "vpnActive": boolean,
  "tlsVersion": "string",
  "userAgent": "string"
}
```

---

## 7. Continuous Verification

### 7.1 Re-verification Schedule

| Resource Sensitivity | Verification Interval |
|---------------------|----------------------|
| Public Resources | 60 minutes |
| Internal Resources | 30 minutes |
| Sensitive Resources | 15 minutes |
| Critical Resources | 5 minutes |

### 7.2 Verification Triggers

Immediate re-verification required when:

- Location change detected (> 50km from last check)
- Network change detected (different IP subnet)
- Behavioral anomaly detected
- Failed access attempt to high-value resource
- External threat intelligence indicates compromise
- Time-based (as per schedule above)

### 7.3 Verification Actions

Based on re-verification results:

```javascript
if (trustScore < MINIMUM_THRESHOLD) {
    // Immediate revocation
    revokeAccess(session);
    terminateSession(session);
    notifyUser("ACCESS_REVOKED");
    alertSecurityTeam(session, trustScore);
} else if (trustScore < STEP_UP_THRESHOLD) {
    // Require additional authentication
    requireStepUpAuthentication(session);
    limitAccessScope(session);
} else {
    // Continue with enhanced monitoring
    increaseMonitoringLevel(session);
    logAccessPatterns(session);
}
```

---

## 8. Microsegmentation

### 8.1 Network Segmentation Strategy

```
┌─────────────────────────────────────────────────┐
│              External Network                    │
└─────────────────┬───────────────────────────────┘
                  │
          ┌───────▼───────┐
          │  DMZ Zone     │
          │  (Public)     │
          └───────┬───────┘
                  │
          ┌───────▼───────┐
          │  Gateway PEP  │
          └───────┬───────┘
                  │
     ┌────────────┼────────────┐
     │            │            │
┌────▼────┐  ┌───▼────┐  ┌───▼────┐
│ Internal│  │Sensitive│  │Critical│
│  Zone   │  │  Zone  │  │  Zone  │
│ (Apps)  │  │ (Data) │  │ (PII)  │
└─────────┘  └────────┘  └────────┘
```

### 8.2 Segment Access Policies

Each segment has independent access policies:

#### Internal Zone
- Trust Score Required: ≥ 70
- MFA Required: Yes
- Device Compliance: Basic
- Monitoring Level: Standard

#### Sensitive Zone
- Trust Score Required: ≥ 80
- MFA Required: Yes (2+ factors)
- Device Compliance: Full
- Monitoring Level: Enhanced

#### Critical Zone
- Trust Score Required: ≥ 90
- MFA Required: Yes (3+ factors, including biometric)
- Device Compliance: Full + MDM
- Monitoring Level: Maximum
- Additional: Privileged Access Management (PAM)

---

## 9. Least Privilege Access

### 9.1 Just-In-Time (JIT) Access

Temporary elevation of privileges:

```json
{
  "accessRequestId": "string",
  "userId": "string",
  "resourceId": "string",
  "requestedActions": ["read", "write", "delete"],
  "justification": "string",
  "duration": 3600,
  "approvalRequired": boolean,
  "approvers": ["string"],
  "conditions": {
    "timeWindow": {
      "start": "ISO-8601",
      "end": "ISO-8601"
    },
    "ipWhitelist": ["string"],
    "mfaRequired": true
  }
}
```

### 9.2 Time-Limited Access

All access grants are time-limited:

| Resource Type | Default Duration | Maximum Duration |
|---------------|-----------------|------------------|
| Public | 8 hours | 24 hours |
| Internal | 4 hours | 8 hours |
| Sensitive | 1 hour | 4 hours |
| Critical | 30 minutes | 2 hours |

---

## 10. Policy Framework

### 10.1 Policy Structure

```json
{
  "policyId": "string",
  "name": "string",
  "description": "string",
  "priority": number,
  "enabled": boolean,
  "conditions": {
    "userAttributes": {
      "groups": ["string"],
      "roles": ["string"],
      "department": "string"
    },
    "deviceRequirements": {
      "minComplianceScore": number,
      "allowedDeviceTypes": ["string"],
      "mdmRequired": boolean
    },
    "networkConstraints": {
      "allowedNetworks": ["string"],
      "blockedCountries": ["string"],
      "vpnRequired": boolean
    },
    "timeConstraints": {
      "allowedHours": "string",
      "allowedDays": ["string"],
      "timezone": "string"
    }
  },
  "actions": {
    "decision": "allow|deny|step-up",
    "maxDuration": number,
    "allowedActions": ["string"],
    "monitoringLevel": "standard|enhanced|maximum"
  }
}
```

---

## 11. Logging and Auditing

### 11.1 Required Audit Logs

All Zero Trust events must be logged:

- Access requests (allow/deny/step-up)
- Trust score calculations
- Policy evaluations
- Authentication events
- Device compliance changes
- Network context changes
- Session lifecycle events
- Policy changes

### 11.2 Log Format

```json
{
  "timestamp": "ISO-8601",
  "eventId": "string",
  "eventType": "access_request|policy_decision|auth_event|...",
  "severity": "info|warning|critical",
  "userId": "string",
  "deviceId": "string",
  "sourceIP": "string",
  "resourceId": "string",
  "action": "string",
  "decision": "allow|deny|step-up",
  "trustScore": number,
  "policyId": "string",
  "riskFactors": ["string"],
  "metadata": {}
}
```

### 11.3 Retention Requirements

| Log Type | Retention Period | Storage Location |
|----------|-----------------|------------------|
| Access Logs | 1 year | Hot storage (90 days), cold storage (remainder) |
| Audit Logs | 7 years | Compliance archive |
| Security Events | 2 years | SIEM system |
| Threat Intel | 90 days | Threat database |

---

## 12. Compliance and Standards

### 12.1 Alignment with Standards

WIA-SEC-005 aligns with:

- **NIST SP 800-207** - Zero Trust Architecture
- **NIST SP 800-63B** - Digital Identity Guidelines
- **ISO/IEC 27001** - Information Security Management
- **CISA Zero Trust Maturity Model**
- **DoD Zero Trust Reference Architecture**

### 12.2 Regulatory Compliance

Supports compliance with:

- GDPR (General Data Protection Regulation)
- HIPAA (Health Insurance Portability and Accountability Act)
- PCI DSS (Payment Card Industry Data Security Standard)
- SOX (Sarbanes-Oxley Act)
- FedRAMP (Federal Risk and Authorization Management Program)

---

## 13. Implementation Phases

### Phase 1: Foundation (This Document)
- Core architecture design
- Trust scoring model
- Identity and device verification
- Basic policy framework

### Phase 2: Data Formats (See PHASE-2-DATA.md)
- Standardized data schemas
- API specifications
- Message formats

### Phase 3: Protocol (See PHASE-3-PROTOCOL.md)
- Access request protocol
- Verification flows
- Session management

### Phase 4: Integration (See PHASE-4-INTEGRATION.md)
- IAM integration
- SIEM integration
- EDR/XDR integration
- API Gateway integration

---

## 14. Security Considerations

### 14.1 Threat Model

Zero Trust protects against:

- **Lateral Movement** - Microsegmentation limits blast radius
- **Credential Theft** - MFA and continuous verification
- **Insider Threats** - Least privilege and monitoring
- **Device Compromise** - Device posture assessment
- **Network-Based Attacks** - No network location trust

### 14.2 Attack Scenarios

| Attack | Zero Trust Mitigation |
|--------|----------------------|
| Phished credentials | MFA required, behavior analysis detects anomaly |
| Compromised device | Device compliance check fails, access denied |
| Lateral movement | Microsegmentation blocks unauthorized segments |
| Privilege escalation | Least privilege, JIT access only |
| Session hijacking | Continuous verification detects context changes |

---

## 15. Performance Considerations

### 15.1 Latency Requirements

| Operation | Target Latency | Maximum Latency |
|-----------|---------------|-----------------|
| Trust Score Calculation | < 100ms | < 500ms |
| Policy Decision | < 50ms | < 200ms |
| Authentication | < 1s | < 3s |
| Session Establishment | < 2s | < 5s |

### 15.2 Scalability Targets

- Support 100,000+ concurrent users
- Process 10,000+ access requests per second
- Store 1 billion+ audit events
- Maintain 99.99% availability

---

## 16. References

1. NIST SP 800-207: Zero Trust Architecture
   https://doi.org/10.6028/NIST.SP.800-207

2. CISA Zero Trust Maturity Model
   https://www.cisa.gov/zero-trust-maturity-model

3. NSA Zero Trust Security Model
   https://www.nsa.gov/Press-Room/Cybersecurity-Advisories-Guidance/

4. Google BeyondCorp Research
   https://cloud.google.com/beyondcorp

5. Microsoft Zero Trust Framework
   https://www.microsoft.com/en-us/security/business/zero-trust

---

## Appendix A: Glossary

- **PDP (Policy Decision Point)**: Component that evaluates access requests
- **PEP (Policy Enforcement Point)**: Component that enforces access decisions
- **PAP (Policy Administration Point)**: Component that manages policies
- **JIT (Just-In-Time)**: Temporary privilege elevation
- **MDM/UEM**: Mobile/Unified Endpoint Management
- **SIEM**: Security Information and Event Management
- **EDR**: Endpoint Detection and Response
- **RBAC**: Role-Based Access Control
- **ABAC**: Attribute-Based Access Control

---

**Document Status:** ✅ Complete
**Next Phase:** [PHASE-2-DATA.md](./PHASE-2-DATA.md)

---

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