Security Overview

# Security Overview

This document provides a comprehensive overview of the security architecture, practices, and procedures implemented in the AI Knowledge Website system.

## Table of Contents

1. [Security Architecture](#security-architecture)
2. [Authentication and Authorization](#authentication-and-authorization)
3. [Data Protection](#data-protection)
4. [Network Security](#network-security)
5. [Application Security](#application-security)
6. [Infrastructure Security](#infrastructure-security)
7. [Monitoring and Incident Response](#monitoring-and-incident-response)
8. [Compliance and Governance](#compliance-and-governance)
9. [Security Policies](#security-policies)
10. [Threat Model](#threat-model)

## Security Architecture

### Zero-Trust Security Model

The AI Knowledge Website implements a zero-trust security architecture with the following principles:

- **Never Trust, Always Verify**: All requests are authenticated and authorized
- **Principle of Least Privilege**: Minimal access rights for users and systems
- **Defense in Depth**: Multiple layers of security controls
- **Assume Breach**: Design for containment and rapid response

### Security Layers

```
┌─────────────────────────────────────────────────────────────────┐
│                        Edge Security                            │
│  ┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐  │
│  │   CDN/WAF       │ │  Rate Limiting  │ │  DDoS Protection│  │
│  └─────────────────┘ └─────────────────┘ └─────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────┐
│                    Application Security                         │
│  ┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐  │
│  │ Authentication  │ │  Authorization  │ │ Input Validation│  │
│  └─────────────────┘ └─────────────────┘ └─────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────┐
│                     Data Security                               │
│  ┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐  │
│  │  Encryption     │ │  Data Masking   │ │  Access Logging │  │
│  └─────────────────┘ └─────────────────┘ └─────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
┌─────────────────────────────────────────────────────────────────┐
│                 Infrastructure Security                         │
│  ┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐  │
│  │ Network Security│ │ Container Security│ │ Secrets Mgmt  │  │
│  └─────────────────┘ └─────────────────┘ └─────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
```

## Authentication and Authorization

### API Authentication

**JWT Token-Based Authentication:**

```python
# Token structure
{
  "sub": "user_id",
  "role": "admin|editor|reader",
  "permissions": ["content:read", "content:write", "pipeline:execute"],
  "exp": 1704067200,
  "iat": 1704063600,
  "iss": "ai-knowledge-api"
}
```

**Token Management:**
- Access tokens: 1-hour expiration
- Refresh tokens: 30-day expiration with rotation
- API keys: Long-lived for service-to-service communication
- Token revocation support for compromised credentials

### Role-Based Access Control (RBAC)

| Role | Permissions | Use Case |
|------|-------------|----------|
| **Super Admin** | All permissions | System administration |
| **Admin** | Content, pipeline, config management | Content administrators |
| **Editor** | Content creation, editing, publishing | Content creators |
| **Pipeline** | Pipeline execution, status monitoring | Automated systems |
| **Reader** | Read-only access to published content | Public API consumers |

### Permission System

```yaml
permissions:
  content:
    - read: Access to published content
    - write: Create and edit content
    - delete: Remove content items
    - publish: Publish draft content
  
  pipeline:
    - execute: Run pipeline jobs
    - monitor: View pipeline status
    - configure: Modify pipeline settings
  
  admin:
    - users: Manage user accounts
    - system: System configuration
    - security: Security settings
```

## Data Protection

### Data Classification

**Classification Levels:**

1. **Public**: Published content, API documentation
2. **Internal**: Processing metadata, system logs
3. **Confidential**: User data, API keys, configuration
4. **Restricted**: Security keys, personal identifiers

### Encryption Standards

**Data at Rest:**
- Database: AES-256 encryption with key rotation
- File storage: AES-256 encryption with customer-managed keys
- Backups: Encrypted with separate key hierarchy

**Data in Transit:**
- TLS 1.3 for all external communications
- mTLS for service-to-service communication
- Certificate pinning for critical connections

**Key Management:**
- AWS KMS/Google Cloud KMS for key management
- Hardware Security Modules (HSM) for key storage
- Automated key rotation every 90 days
- Separate keys per environment and data type

### Data Loss Prevention (DLP)

**Content Scanning:**
- Automated detection of sensitive data patterns
- PII detection and redaction in logs
- API key detection and alerting
- Credit card and social security number detection

**Data Handling Policies:**
- No sensitive data in logs or error messages
- Automatic data retention and deletion
- Data minimization principles
- Privacy-by-design architecture

## Network Security

### Network Architecture

**Network Segmentation:**
```
Internet → WAF → Load Balancer → DMZ → Internal Network
                      ↓
               Application Layer
                      ↓
               Database Layer (Private Subnet)
```

**Security Controls:**
- Web Application Firewall (WAF) with OWASP rule sets
- Network ACLs and security groups
- VPC isolation with private subnets
- Egress filtering and monitoring

### API Security

**Rate Limiting:**
```python
# Rate limiting tiers
RATE_LIMITS = {
    'public_api': '100/hour',
    'authenticated_api': '1000/hour', 
    'premium_api': '10000/hour',
    'pipeline_api': '100/minute'
}

# Adaptive rate limiting based on behavior
ADAPTIVE_LIMITS = {
    'suspicious_behavior': '10/hour',
    'failed_authentication': '5/hour',
    'known_good_client': '2000/hour'
}
```

**Input Validation:**
- Comprehensive input sanitization
- SQL injection prevention
- XSS protection with CSP headers
- File upload restrictions and scanning
- Request size limits and timeout controls

## Application Security

### Secure Coding Practices

**Input Validation:**
```python
from pydantic import BaseModel, validator
import bleach

class ContentInput(BaseModel):
    title: str
    content: str
    
    @validator('title')
    def validate_title(cls, v):
        # Sanitize HTML and prevent XSS
        return bleach.clean(v, tags=[], strip=True)[:200]
    
    @validator('content')
    def validate_content(cls, v):
        # Allow safe HTML tags only
        allowed_tags = ['p', 'br', 'strong', 'em', 'ul', 'ol', 'li']
        return bleach.clean(v, tags=allowed_tags, strip=True)
```

**SQL Injection Prevention:**
```python
# Good: Parameterized queries
def get_content_by_id(content_id: str) -> Optional[Content]:
    query = """
        SELECT * FROM content_items 
        WHERE id = %s AND status = 'published'
    """
    return session.execute(query, (content_id,)).fetchone()

# Avoid: String concatenation (vulnerable to injection)
# query = f"SELECT * FROM content_items WHERE id = '{content_id}'"
```

### Content Security Policy (CSP)

```javascript
// CSP Header Configuration
const cspDirectives = {
  'default-src': ["'self'"],
  'script-src': ["'self'", "'unsafe-inline'", 'https://cdnjs.cloudflare.com'],
  'style-src': ["'self'", "'unsafe-inline'", 'https://fonts.googleapis.com'],
  'img-src': ["'self'", 'data:', 'https:'],
  'font-src': ["'self'", 'https://fonts.gstatic.com'],
  'connect-src': ["'self'", 'https://api.ai-knowledge.org'],
  'frame-ancestors': ["'none'"],
  'base-uri': ["'self'"],
  'object-src': ["'none'"]
};
```

### Security Headers

```http
# Standard security headers
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-XSS-Protection: 1; mode=block
Referrer-Policy: strict-origin-when-cross-origin
Permissions-Policy: geolocation=(), microphone=(), camera=()
```

## Infrastructure Security

### Container Security

**Image Security:**
```dockerfile
# Use minimal base images
FROM python:3.11-slim

# Run as non-root user
RUN groupadd -r appuser && useradd -r -g appuser appuser
USER appuser

# Scan for vulnerabilities
# docker scout cve ai-knowledge/pipeline:latest
```

**Runtime Security:**
- Read-only root filesystems
- No privileged containers
- Resource limits and quotas
- Security contexts and pod security policies

### Kubernetes Security

**Pod Security Standards:**
```yaml
apiVersion: v1
kind: Pod
metadata:
  name: ai-knowledge-pipeline
spec:
  securityContext:
    runAsNonRoot: true
    runAsUser: 1000
    fsGroup: 2000
  containers:
  - name: pipeline
    securityContext:
      allowPrivilegeEscalation: false
      readOnlyRootFilesystem: true
      capabilities:
        drop:
        - ALL
```

**Network Policies:**
```yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: ai-knowledge-network-policy
spec:
  podSelector:
    matchLabels:
      app: ai-knowledge
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          role: frontend
  egress:
  - to:
    - podSelector:
        matchLabels:
          role: database
```

### Secrets Management

**Kubernetes Secrets:**
```yaml
apiVersion: v1
kind: Secret
metadata:
  name: ai-knowledge-secrets
type: Opaque
data:
  database-url: <base64-encoded-value>
  api-key: <base64-encoded-value>
```

**External Secrets Integration:**
- AWS Secrets Manager / Google Secret Manager
- HashiCorp Vault integration
- Automatic secret rotation
- Audit trails for secret access

## Monitoring and Incident Response

### Security Monitoring

**Log Monitoring:**
```python
# Security event logging
import structlog

security_logger = structlog.get_logger("security")

def log_authentication_attempt(username: str, success: bool, ip_address: str):
    security_logger.info(
        "authentication_attempt",
        username=username,
        success=success,
        ip_address=ip_address,
        event_type="auth",
        severity="medium" if not success else "low"
    )
```

**Metrics and Alerting:**
- Failed authentication attempts
- Unusual traffic patterns
- Privilege escalation attempts
- Data exfiltration indicators
- Security policy violations

### Intrusion Detection

**Application-Level Detection:**
- Anomalous API usage patterns
- Suspicious user behavior
- Automated attack signatures
- Business logic violations

**Infrastructure-Level Detection:**
- Network traffic anomalies
- Process execution monitoring
- File integrity monitoring
- Container runtime security

## Compliance and Governance

### Regulatory Compliance

**GDPR Compliance:**
- Data subject rights implementation
- Privacy by design principles
- Data Processing Records (ROPA)
- Data Protection Impact Assessments (DPIA)

**SOC 2 Type II:**
- Security controls documentation
- Operational effectiveness testing
- Continuous monitoring programs
- Annual compliance audits

### Data Governance

**Data Retention:**
```python
# Automated data retention policies
RETENTION_POLICIES = {
    'user_data': timedelta(days=2555),  # 7 years
    'access_logs': timedelta(days=90),   # 90 days
    'audit_logs': timedelta(days=2555),  # 7 years
    'content_snapshots': timedelta(days=365)  # 1 year
}
```

**Data Subject Rights:**
- Right to access personal data
- Right to rectification
- Right to erasure (right to be forgotten)
- Right to data portability
- Right to object to processing

## Security Policies

### Password Policy

**Requirements:**
- Minimum 12 characters
- Must include uppercase, lowercase, numbers, symbols
- No common passwords or personal information
- Password rotation every 90 days
- No password reuse (last 12 passwords)

### Access Control Policy

**Principles:**
- Principle of least privilege
- Regular access reviews (quarterly)
- Immediate revocation upon termination
- Multi-factor authentication for all accounts
- Privileged access monitoring

### Incident Response Policy

**Response Levels:**

| Level | Response Time | Escalation |
|-------|---------------|------------|
| Critical | 15 minutes | CISO, Legal |
| High | 1 hour | Security Team |
| Medium | 4 hours | DevOps Team |
| Low | 24 hours | Developer |

## Threat Model

### Threat Actors

**External Threats:**
- Script kiddies: Automated scanning and exploitation
- Criminal organizations: Data theft and ransomware
- Nation-state actors: Advanced persistent threats
- Competitors: Industrial espionage

**Internal Threats:**
- Malicious insiders: Privilege abuse
- Negligent employees: Accidental exposure
- Compromised accounts: Lateral movement
- Third-party vendors: Supply chain attacks

### Attack Vectors

**Most Likely Threats:**

1. **Web Application Attacks (High)**
   - SQL injection
   - Cross-site scripting (XSS)
   - Authentication bypass
   - Business logic flaws

2. **API Abuse (Medium)**
   - Rate limit bypass
   - Data scraping
   - Authentication token theft
   - Parameter pollution

3. **Infrastructure Attacks (Medium)**
   - Container escape
   - Kubernetes privilege escalation
   - Network lateral movement
   - Credential theft

### Risk Assessment

**Risk Matrix:**

| Threat | Likelihood | Impact | Risk Level | Mitigation |
|--------|------------|--------|------------|------------|
| Data Breach | Medium | High | High | Encryption, Access Controls |
| DDoS Attack | High | Medium | High | CDN, Rate Limiting |
| API Abuse | High | Low | Medium | Authentication, Monitoring |
| Insider Threat | Low | High | Medium | Access Reviews, Monitoring |

## Security Testing

### Automated Security Testing

**Static Application Security Testing (SAST):**
```yaml
# GitHub Actions security scan
- name: Run Bandit Security Check
  run: |
    pip install bandit
    bandit -r pipelines/ -f json -o bandit-report.json

- name: Run Semgrep SAST
  uses: returntocorp/semgrep-action@v1
  with:
    config: >-
      p/security-audit
      p/secrets
```

**Dynamic Application Security Testing (DAST):**
- OWASP ZAP integration in CI/CD
- Regular penetration testing
- API security testing
- Container vulnerability scanning

### Manual Security Testing

**Quarterly Security Reviews:**
- Code review for security issues
- Architecture review for security flaws
- Configuration review for misconfigurations
- Access control review for violations

## Incident Response Procedures

### Immediate Response (0-15 minutes)

1. **Detect and Assess**
   - Automated alerting triggers
   - Initial severity assessment
   - Stakeholder notification

2. **Contain**
   - Isolate affected systems
   - Preserve evidence
   - Prevent further damage

### Short-term Response (15 minutes - 4 hours)

1. **Investigate**
   - Root cause analysis
   - Impact assessment
   - Evidence collection

2. **Communicate**
   - Internal stakeholder updates
   - Customer notification (if required)
   - Regulatory reporting (if required)

### Recovery and Lessons Learned (4+ hours)

1. **Recover**
   - System restoration
   - Service validation
   - Performance monitoring

2. **Learn**
   - Post-incident review
   - Process improvements
   - Security control updates

---

**Security Contacts:**
- **Security Team**: [email protected]
- **Incident Response**: [email protected]
- **Emergency**: +1-XXX-XXX-XXXX (24/7 security hotline)

**Last Updated**: January 2024  
**Classification**: Internal  
**Review Cycle**: Quarterly