Implementation Guide¶

This guide provides step-by-step instructions for implementing ZeroTrustKerberosLink in your environment. Each section focuses on a specific aspect of the implementation process.

Table of Contents¶

Prerequisites
Architecture Overview
Installation
Configuration
AWS Integration
Security Hardening
Testing
Monitoring
Troubleshooting

Prerequisites¶

Before implementing ZeroTrustKerberosLink, ensure your environment meets the following requirements:

System Requirements¶

Linux-based operating system (Ubuntu 20.04+ or RHEL/CentOS 8+)
Docker 20.10+ or Kubernetes 1.19+
AWS CLI v2
Python 3.8+

Network Requirements¶

Outbound access to AWS services
Connectivity to your Kerberos KDC
Recommended: Dedicated subnet for ZeroTrustKerberosLink

AWS Account Requirements¶

IAM permissions to create roles and policies
AWS STS service enabled
Cross-account access configured (if applicable)

Kerberos Requirements¶

Functional Kerberos infrastructure
Service principal for ZeroTrustKerberosLink
Keytab file for the service principal

Architecture Overview¶

ZeroTrustKerberosLink consists of several components working together:

Core Components¶

Authentication Service: Handles Kerberos authentication
Policy Engine: Evaluates access policies and context
AWS Connector: Manages AWS role assumption
Redis Cache: Stores session information
Monitoring Agent: Collects metrics and logs

Deployment Options¶

Standalone: Single-instance deployment
High Availability: Multi-instance deployment with load balancing
Kubernetes: Containerized deployment on Kubernetes

Network Architecture¶

┌─────────────────┐     ┌───────────────────┐     ┌──────────────┐
│                 │     │                   │     │              │
│  Enterprise     │◄───▶│  ZeroTrust        │◄───▶│  AWS         │
│  Network        │     │  KerberosLink     │     │  Services    │
│                 │     │                   │     │              │
└─────────────────┘     └───────────────────┘     └──────────────┘
        ▲                        ▲
        │                        │
        ▼                        ▼
┌─────────────────┐     ┌───────────────────┐
│                 │     │                   │
│  Kerberos KDC   │     │  Redis Cache      │
│                 │     │                   │
└─────────────────┘     └───────────────────┘

Installation¶

Follow these steps to install ZeroTrustKerberosLink:

Using Docker¶

Pull the Docker image:

docker pull zerotrustkerberos/kerberos-aws-proxy:latest

Create a configuration directory:

mkdir -p /etc/zerotrustkerberos/config

Run the container:

docker run -d \
  --name zerotrustkerberos \
  -v /etc/zerotrustkerberos:/etc/zerotrustkerberos \
  -p 8080:8080 \
  zerotrustkerberos/kerberos-aws-proxy:latest

Using Kubernetes¶

Create a namespace:

kubectl create namespace zerotrustkerberos

Create a ConfigMap for configuration:

kubectl create configmap zerotrustkerberos-config \
  --from-file=/path/to/config.yaml \
  -n zerotrustkerberos

Create a Secret for sensitive data:

kubectl create secret generic zerotrustkerberos-secrets \
  --from-file=/path/to/krb5.keytab \
  -n zerotrustkerberos

Apply the deployment manifest:

kubectl apply -f zerotrustkerberos-deployment.yaml -n zerotrustkerberos

From Source¶

Clone the repository:

git clone https://github.com/zerotrustkerberos/kerberos-aws-proxy.git
cd kerberos-aws-proxy

Install dependencies:

pip install -r requirements.txt

Build the application:

make build

Install the application:

make install

Configuration¶

Configure ZeroTrustKerberosLink using the following steps:

Basic Configuration¶

Create a config.yaml file with the following structure:

server:
  host: "0.0.0.0"
  port: 8080
  workers: 4

kerberos:
  service_principal: "HTTP/zerotrustkerberos.example.com@EXAMPLE.COM"
  keytab_path: "/etc/zerotrustkerberos/krb5.keytab"
  realm: "EXAMPLE.COM"

aws:
  region: "us-west-2"
  role_mappings:
    - kerberos_principal: "admin@EXAMPLE.COM"
      aws_role: "arn:aws:iam::123456789012:role/AdminRole"
    - kerberos_principal: "developer@EXAMPLE.COM"
      aws_role: "arn:aws:iam::123456789012:role/DeveloperRole"

redis:
  host: "localhost"
  port: 6379
  use_tls: true

Advanced Configuration¶

For advanced security features, extend your configuration:

security:
  input_validation:
    enabled: true
    validate_kerberos_principal: true
    validate_aws_role_arn: true

  rate_limiting:
    enabled: true
    requests_per_minute: 30
    burst: 10

  session:
    default_duration: 3600  # 1 hour
    max_duration: 14400  # 4 hours
    renewal_enabled: true

logging:
  level: "info"
  format: "json"
  output: "file"
  file_path: "/var/log/zerotrustkerberos/app.log"

Environment Variables¶

You can override configuration using environment variables:

Environment Variable	Description	Default
`ZEROTRUST_SERVER_PORT`	Server port	8080
`ZEROTRUST_KERBEROS_KEYTAB_PATH`	Path to keytab file	/etc/zerotrustkerberos/krb5.keytab
`ZEROTRUST_AWS_REGION`	AWS region	us-west-2
`ZEROTRUST_REDIS_HOST`	Redis host	localhost
`ZEROTRUST_LOG_LEVEL`	Logging level	info

AWS Integration¶

Configure AWS integration for ZeroTrustKerberosLink:

IAM Role Setup¶

Create an IAM role for ZeroTrustKerberosLink:

aws iam create-role \
  --role-name ZeroTrustKerberosLinkRole \
  --assume-role-policy-document file://trust-policy.json

Example trust-policy.json:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "ec2.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

Attach necessary policies:

aws iam attach-role-policy \
  --role-name ZeroTrustKerberosLinkRole \
  --policy-arn arn:aws:iam::aws:policy/AmazonSTS-AssumeRoleAccess

User Role Mapping¶

Create roles for different user types:

aws iam create-role \
  --role-name AdminRole \
  --assume-role-policy-document file://admin-trust-policy.json

Configure role mappings in config.yaml:

aws:
  role_mappings:
    - kerberos_principal: "admin@EXAMPLE.COM"
      aws_role: "arn:aws:iam::123456789012:role/AdminRole"
      conditions:
        ip_ranges: ["10.0.0.0/8"]
        time_window: ["08:00-18:00"]
    - kerberos_principal: "*@EXAMPLE.COM"
      aws_role: "arn:aws:iam::123456789012:role/DefaultRole"

Cross-Account Access¶

For cross-account access:

Create roles in target accounts:

aws iam create-role \
  --role-name CrossAccountRole \
  --assume-role-policy-document file://cross-account-trust-policy.json

Configure cross-account mappings:

aws:
  cross_account_mappings:
    - source_principal: "admin@EXAMPLE.COM"
      target_accounts:
        - account_id: "987654321098"
          role_name: "CrossAccountAdminRole"
        - account_id: "876543210987"
          role_name: "CrossAccountAdminRole"

Security Hardening¶

Implement security hardening measures:

TLS Configuration¶

Generate TLS certificates:

openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
  -keyout /etc/zerotrustkerberos/tls/private.key \
  -out /etc/zerotrustkerberos/tls/certificate.crt

Configure TLS in config.yaml:

server:
  tls:
    enabled: true
    cert_path: "/etc/zerotrustkerberos/tls/certificate.crt"
    key_path: "/etc/zerotrustkerberos/tls/private.key"
    min_version: "TLSv1.2"

Security Headers¶

Configure security headers:

security:
  headers:
    content_security_policy: "default-src 'self'"
    x_content_type_options: "nosniff"
    x_frame_options: "DENY"
    strict_transport_security: "max-age=31536000; includeSubDomains"

Input Validation¶

Enable comprehensive input validation:

security:
  input_validation:
    enabled: true
    validate_kerberos_principal: true
    validate_aws_role_arn: true
    validate_client_context: true
    sanitize_headers: true

Secure Redis Communication¶

Configure secure Redis communication:

redis:
  host: "redis.example.com"
  port: 6379
  use_tls: true
  cert_path: "/etc/zerotrustkerberos/tls/redis-ca.crt"
  auth:
    username: "zerotrustkerberos"
    password_file: "/etc/zerotrustkerberos/secrets/redis-password"

Testing¶

Test your ZeroTrustKerberosLink implementation:

Authentication Testing¶

Test Kerberos authentication:

kinit testuser@EXAMPLE.COM
curl --negotiate -u : https://zerotrustkerberos.example.com/auth/test

Test AWS role assumption:

curl --negotiate -u : https://zerotrustkerberos.example.com/auth/aws

Load Testing¶

Run load tests to ensure performance:

ab -n 1000 -c 10 https://zerotrustkerberos.example.com/auth/test

Security Testing¶

Run the built-in security test suite:

zerotrustkerberos-cli security-test --config /etc/zerotrustkerberos/config.yaml

Verify security headers:

curl -I https://zerotrustkerberos.example.com/auth/test

Monitoring¶

Set up monitoring for ZeroTrustKerberosLink:

Metrics Collection¶

Enable Prometheus metrics:

monitoring:
  prometheus:
    enabled: true
    endpoint: "/metrics"

Configure Grafana dashboards:

kubectl apply -f zerotrustkerberos-grafana-dashboard.yaml

Log Management¶

Configure log forwarding:

logging:
  forward:
    enabled: true
    type: "elasticsearch"
    endpoint: "https://elasticsearch.example.com:9200"
    index: "zerotrustkerberos-logs"

Set up log alerts:

monitoring:
  alerts:
    - name: "high_auth_failure_rate"
      query: "auth_failures > 10"
      threshold: 5
      duration: "5m"
      notification: "slack"

Health Checks¶

Configure health check endpoints:

server:
  health_check:
    enabled: true
    endpoint: "/health"
    include_details: true

Troubleshooting¶

Common issues and their solutions:

Authentication Issues¶

Issue: Kerberos authentication fails

Solution: 1. Verify keytab file permissions:

ls -la /etc/zerotrustkerberos/krb5.keytab

2. Check service principal in keytab:

klist -kt /etc/zerotrustkerberos/krb5.keytab

3. Ensure time synchronization:

chronyc tracking

AWS Integration Issues¶

Issue: Unable to assume AWS role

Solution: 1. Check IAM role trust policy:

aws iam get-role --role-name AdminRole

2. Verify role mapping configuration:

cat /etc/zerotrustkerberos/config.yaml | grep -A 10 role_mappings

3. Check AWS STS service status:

aws sts get-caller-identity

Performance Issues¶

Issue: High latency in authentication

Solution: 1. Increase worker processes:

server:
  workers: 8

2. Enable Redis caching:

cache:
  enabled: true
  ttl: 300

3. Optimize AWS role assumption:

aws:
  connection_pool_size: 10
  timeout: 5

For more detailed troubleshooting, refer to the Troubleshooting Guide.

Next Steps¶

After completing the basic implementation: