cloud-security

name	Cloud Security
category	cybersecurity
description	Securing cloud infrastructure, services, and workloads across AWS, GCP, and Azure environments
tags	["cloud","aws","gcp","azure","iam","infrastructure-security"]
version	1.0

Cloud Security

What I Do

I provide guidance on securing cloud-native infrastructure and workloads. This covers identity and access management (IAM), network segmentation, encryption at rest and in transit, secure configuration of cloud services, infrastructure-as-code security scanning, and compliance monitoring across major cloud providers.

When to Use Me

• Designing IAM policies and role hierarchies for cloud accounts
• Configuring VPCs, security groups, and network ACLs
• Implementing encryption for storage, databases, and message queues
• Scanning Terraform/CloudFormation templates for misconfigurations
• Setting up cloud audit logging and monitoring
• Achieving compliance (SOC 2, HIPAA, PCI-DSS) in cloud environments

Core Concepts

1. Shared Responsibility Model: Cloud providers secure the infrastructure; customers secure their configurations, data, and applications running on it.
2. IAM Least Privilege: Grant only the permissions required for a specific task using fine-grained policies, conditions, and permission boundaries.
3. Network Segmentation: Use VPCs, subnets, security groups, and NACLs to isolate workloads and restrict lateral movement.
4. Encryption Everywhere: Encrypt data at rest (KMS-managed keys) and in transit (TLS 1.2+) for all services.
5. Infrastructure as Code Security: Scan IaC templates (Terraform, CloudFormation) for misconfigurations before deployment.
6. Cloud Audit Logging: Enable CloudTrail (AWS), Cloud Audit Logs (GCP), or Activity Log (Azure) and ship to a centralized SIEM.
7. Service Control Policies: Organization-level guardrails that restrict what member accounts can do regardless of IAM permissions.
8. Secrets Management: Use cloud-native secrets managers (Secrets Manager, Parameter Store, Vault) instead of hardcoded credentials.
9. Immutable Infrastructure: Deploy new instances instead of patching running ones to reduce configuration drift.

Code Examples

1. Least-Privilege IAM Policy (AWS Terraform)

resource "aws_iam_policy" "s3_reader" {
  name        = "s3-data-reader"
  description = "Read-only access to specific S3 bucket"

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Sid      = "AllowReadSpecificBucket"
        Effect   = "Allow"
        Action   = ["s3:GetObject", "s3:ListBucket"]
        Resource = [
          "arn:aws:s3:::my-data-bucket",
          "arn:aws:s3:::my-data-bucket/*"
        ]
        Condition = {
          StringEquals = {
            "aws:RequestedRegion" = "us-east-1"
          }
        }
      }
    ]
  })
}

2. Secure VPC with Private Subnets (Terraform)

resource "aws_vpc" "main" {
  cidr_block           = "10.0.0.0/16"
  enable_dns_support   = true
  enable_dns_hostnames = true
}

resource "aws_subnet" "private" {
  vpc_id                  = aws_vpc.main.id
  cidr_block              = "10.0.1.0/24"
  map_public_ip_on_launch = false
  availability_zone       = "us-east-1a"
}

resource "aws_security_group" "app" {
  vpc_id = aws_vpc.main.id

  ingress {
    from_port       = 443
    to_port         = 443
    protocol        = "tcp"
    security_groups = [aws_security_group.alb.id]
  }

  egress {
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

3. KMS Encryption for S3 Bucket (Terraform)

resource "aws_kms_key" "data_key" {
  description             = "KMS key for data bucket encryption"
  deletion_window_in_days = 30
  enable_key_rotation     = true
}

resource "aws_s3_bucket_server_side_encryption_configuration" "data" {
  bucket = aws_s3_bucket.data.id

  rule {
    apply_server_side_encryption_by_default {
      sse_algorithm     = "aws:kms"
      kms_master_key_id = aws_kms_key.data_key.arn
    }
    bucket_key_enabled = true
  }
}

resource "aws_s3_bucket_public_access_block" "data" {
  bucket                  = aws_s3_bucket.data.id
  block_public_acls       = true
  block_public_policy     = true
  ignore_public_acls      = true
  restrict_public_buckets = true
}

4. Cloud Audit Logging (AWS CloudTrail Terraform)

resource "aws_cloudtrail" "main" {
  name                          = "org-audit-trail"
  s3_bucket_name                = aws_s3_bucket.trail.id
  include_global_service_events = true
  is_multi_region_trail         = true
  enable_log_file_validation    = true
  kms_key_id                    = aws_kms_key.trail_key.arn

  event_selector {
    read_write_type           = "All"
    include_management_events = true

    data_resource {
      type   = "AWS::S3::Object"
      values = ["arn:aws:s3"]
    }
  }
}

Best Practices

1. Enforce MFA for all human users and require it for sensitive API operations via IAM conditions.
2. Use service accounts and roles instead of long-lived access keys for machine-to-machine authentication.
3. Block public access to storage buckets and databases by default using account-level settings.
4. Enable key rotation for all KMS keys and rotate access credentials on a regular schedule.
5. Scan IaC templates with tools like tfsec, Checkov, or cfn-nag before applying changes.
6. Tag all resources with owner, environment, and data-classification to support audit and cost tracking.
7. Use VPC endpoints for AWS service access to keep traffic off the public internet.
8. Centralize logging into a dedicated security account with immutable storage and alerting.
9. Apply Service Control Policies at the organization level to prevent disabling of security controls.
10. Review and prune IAM permissions quarterly using access advisor data and unused permission reports.