AWS Security Architecture Skill

Purpose

This skill provides AWS security architecture guidance for the CIA platform deployment, covering VPC network security, IAM least-privilege policies, KMS encryption, CloudTrail auditing, and GuardDuty threat detection. It aligns with Hack23 ISMS and AWS Well-Architected Security Pillar.

When to Use This Skill

Apply this skill when:

• ✅ Designing or modifying AWS infrastructure (CloudFormation)
• ✅ Configuring IAM roles, policies, or permissions
• ✅ Setting up encryption with KMS for data at rest
• ✅ Configuring VPC networking, security groups, or NACLs
• ✅ Enabling audit logging with CloudTrail
• ✅ Setting up threat detection with GuardDuty
• ✅ Reviewing cia-dist-cloudformation templates

Do NOT use for:

• ❌ Application-level security (use secure-code-review skill)
• ❌ CI/CD pipeline security (use github-actions-workflows skill)
• ❌ Data classification decisions (use data-protection skill)

AWS Security Architecture Overview

CIA Platform AWS Architecture
│
├─ VPC (10.0.0.0/16)
│  ├─ Public Subnet (10.0.1.0/24)
│  │  ├─ ALB (Application Load Balancer)
│  │  └─ NAT Gateway
│  │
│  ├─ Private Subnet - App (10.0.2.0/24)
│  │  └─ EC2 / ECS (CIA Application)
│  │
│  └─ Private Subnet - Data (10.0.3.0/24)
│     └─ RDS PostgreSQL (encrypted)
│
├─ Security Services
│  ├─ AWS WAF (on ALB)
│  ├─ AWS Shield (DDoS protection)
│  ├─ GuardDuty (threat detection)
│  ├─ CloudTrail (audit logging)
│  └─ AWS Config (compliance monitoring)
│
└─ Key Management
   └─ KMS (Customer Managed Keys)
      ├─ RDS encryption key
      ├─ S3 encryption key
      └─ Secrets Manager key

VPC Security

Security Group Rules

# Application Security Group - Least Privilege
ApplicationSecurityGroup:
  Type: AWS::EC2::SecurityGroup
  Properties:
    GroupDescription: CIA Application Server
    VpcId: !Ref VPC
    SecurityGroupIngress:
      # Only allow traffic from ALB
      - IpProtocol: tcp
        FromPort: 8080
        ToPort: 8080
        SourceSecurityGroupId: !Ref ALBSecurityGroup
    SecurityGroupEgress:
      # PostgreSQL to database only
      - IpProtocol: tcp
        FromPort: 5432
        ToPort: 5432
        DestinationSecurityGroupId: !Ref DatabaseSecurityGroup
      # HTTPS for external API calls
      - IpProtocol: tcp
        FromPort: 443
        ToPort: 443
        CidrIp: 0.0.0.0/0

# Database Security Group
DatabaseSecurityGroup:
  Type: AWS::EC2::SecurityGroup
  Properties:
    GroupDescription: CIA PostgreSQL Database
    VpcId: !Ref VPC
    SecurityGroupIngress:
      # Only from application servers
      - IpProtocol: tcp
        FromPort: 5432
        ToPort: 5432
        SourceSecurityGroupId: !Ref ApplicationSecurityGroup
    SecurityGroupEgress: []  # No outbound access needed

Network ACLs

NACL Rules (defense in depth):
├─ Allow inbound HTTPS (443) from internet to public subnet
├─ Allow inbound 8080 from public to private app subnet
├─ Allow inbound 5432 from app subnet to data subnet
├─ Deny all other inbound traffic
└─ Allow ephemeral ports for return traffic

IAM Least Privilege

Application IAM Role

# EC2/ECS Task Role - Minimum permissions
CIAApplicationRole:
  Type: AWS::IAM::Role
  Properties:
    RoleName: cia-application-role
    AssumeRolePolicyDocument:
      Version: '2012-10-17'
      Statement:
        - Effect: Allow
          Principal:
            Service: ecs-tasks.amazonaws.com
          Action: sts:AssumeRole
    Policies:
      - PolicyName: cia-app-policy
        PolicyDocument:
          Version: '2012-10-17'
          Statement:
            # Read secrets from Secrets Manager
            - Effect: Allow
              Action:
                - secretsmanager:GetSecretValue
              Resource:
                - !Sub 'arn:aws:secretsmanager:${AWS::Region}:${AWS::AccountId}:secret:cia/*'
            # Write CloudWatch logs
            - Effect: Allow
              Action:
                - logs:CreateLogStream
                - logs:PutLogEvents
              Resource:
                - !Sub 'arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/cia/*'
            # KMS decrypt for database credentials
            - Effect: Allow
              Action:
                - kms:Decrypt
              Resource:
                - !GetAtt CIAEncryptionKey.Arn

IAM Anti-Patterns

# ❌ INSECURE: Overly permissive policy
- Effect: Allow
  Action: '*'
  Resource: '*'

# ❌ INSECURE: Wildcard on sensitive services
- Effect: Allow
  Action: 's3:*'
  Resource: '*'

# ✅ SECURE: Specific actions on specific resources
- Effect: Allow
  Action:
    - s3:GetObject
    - s3:PutObject
  Resource:
    - !Sub 'arn:aws:s3:::cia-data-bucket/*'

KMS Encryption

Key Configuration

CIAEncryptionKey:
  Type: AWS::KMS::Key
  Properties:
    Description: CIA Platform encryption key
    Enabled: true
    EnableKeyRotation: true  # Annual automatic rotation
    KeyPolicy:
      Version: '2012-10-17'
      Statement:
        - Sid: AllowKeyAdministration
          Effect: Allow
          Principal:
            AWS: !Sub 'arn:aws:iam::${AWS::AccountId}:role/admin'
          Action:
            - kms:Create*
            - kms:Describe*
            - kms:Enable*
            - kms:List*
            - kms:Put*
            - kms:Update*
            - kms:Revoke*
            - kms:Disable*
            - kms:Get*
            - kms:Delete*
            - kms:ScheduleKeyDeletion
          Resource: '*'
        - Sid: AllowApplicationUse
          Effect: Allow
          Principal:
            AWS: !GetAtt CIAApplicationRole.Arn
          Action:
            - kms:Decrypt
            - kms:GenerateDataKey
          Resource: '*'

Encryption Scope

Resource	Encryption	Key Type
RDS PostgreSQL	At rest + in transit	KMS CMK
S3 buckets	SSE-KMS	KMS CMK
EBS volumes	At rest	KMS CMK
Secrets Manager	At rest	KMS CMK
CloudWatch Logs	At rest	AWS managed
ALB (TLS)	In transit	ACM certificate

CloudTrail Audit Logging

CIACloudTrail:
  Type: AWS::CloudTrail::Trail
  Properties:
    TrailName: cia-audit-trail
    IsLogging: true
    IsMultiRegionTrail: true
    EnableLogFileValidation: true  # Tamper detection
    IncludeGlobalServiceEvents: true
    S3BucketName: !Ref AuditLogBucket
    CloudWatchLogsLogGroupArn: !GetAtt AuditLogGroup.Arn
    EventSelectors:
      - ReadWriteType: All
        IncludeManagementEvents: true
        DataResources:
          - Type: AWS::S3::Object
            Values: ['arn:aws:s3:::cia-data-bucket/']

GuardDuty Threat Detection

Enabled Findings

GuardDuty Detection Categories:
├─ Reconnaissance: Port scanning, API enumeration
├─ Instance Compromise: Cryptocurrency mining, C&C communication
├─ Account Compromise: Unusual API calls, disabled logging
├─ S3 Compromise: Public bucket access, unusual data transfer
└─ RDS Protection: Unusual login attempts, suspicious queries

Alert Response

Severity	Response Time	Action
Critical	< 1 hour	Immediate investigation, isolate resource
High	< 4 hours	Investigate, assess impact
Medium	< 24 hours	Review, plan remediation
Low	< 1 week	Log, trend analysis

Security Checklist for CloudFormation

CloudFormation Security Review:
□ No hardcoded secrets or credentials
□ IAM roles follow least privilege
□ Security groups restrict inbound/outbound
□ RDS encryption enabled (KMS CMK)
□ S3 buckets private, encrypted, versioned
□ CloudTrail enabled with log validation
□ VPC flow logs enabled
□ ALB uses TLS 1.2+ only
□ Auto-scaling configured for availability
□ Backup retention configured (RDS, S3)
□ Tags applied for cost and security tracking

ISMS Alignment

Control	Requirement	AWS Implementation
ISO 27001 A.8.1	User endpoint devices	Security groups, NACLs
ISO 27001 A.8.9	Configuration management	AWS Config rules
ISO 27001 A.8.15	Logging	CloudTrail, CloudWatch
ISO 27001 A.8.20	Network security	VPC, WAF, Shield
ISO 27001 A.8.24	Cryptography	KMS, ACM, TLS
NIST CSF DE.CM	Continuous monitoring	GuardDuty, Config
CIS Control 3	Data protection	KMS encryption
CIS Control 8	Audit log management	CloudTrail

References

• AWS Well-Architected Security Pillar
• AWS CloudFormation Security Best Practices
• CIS AWS Benchmark
• Hack23 ISMS Infrastructure Security