Identity and Organization Structure
AWS Organizations and Account Strategy AWS Organizations provides centralized management for multiple AWS accounts, enabling hierarchical organization structures with inherited policies and consolidated billing. Security engineers implement multi-account strategies that separate environments (production, staging, development), applications, and tenants into distinct accounts, creating security boundaries that limit blast radius from compromises or misconfigurations. Account separation prevents lateral movement between environments, enables granular cost allocation, and simplifies compliance by isolating regulated workloads. Organizational Units (OUs) group accounts with similar security requirements, enabling policy inheritance and consistent control application across account groups. Service Control Policies Service Control Policies (SCPs) enforce organization-wide guardrails that prevent dangerous operations regardless of IAM permissions within accounts. SCPs implement deny-by-default strategies that explicitly allow required services while blocking risky operations like disabling CloudTrail, creating internet gateways in restricted OUs, or deploying resources in unauthorized regions. Effective SCP design balances security controls with operational flexibility, using condition keys to allow operations in specific contexts while preventing abuse. SCPs should prevent security control circumvention, enforce encryption requirements, and restrict access to sensitive services. IAM Best Practices IAM roles should be preferred over IAM users for all programmatic access, enabling temporary credentials with automatic rotation and eliminating long-lived access keys. AWS SSO (IAM Identity Center) provides centralized identity management with federation to corporate identity providers, enabling single sign-on across AWS accounts with consistent permission sets. Permission boundaries limit the maximum permissions that IAM entities can grant, preventing privilege escalation through IAM policy modifications. Session duration limits reduce the window of opportunity for credential theft, while external IDs prevent confused deputy attacks in cross-account access scenarios. Instance Metadata Service Security IMDSv2 requires session-oriented requests that prevent SSRF attacks from retrieving instance credentials. Organizations should enforce IMDSv2 through SCPs and EC2 launch templates, blocking IMDSv1 access that enables credential theft through web application vulnerabilities. Instance profiles provide EC2 instances with temporary credentials that automatically rotate, eliminating static access keys. Role chaining should be used carefully, as excessive chaining can complicate permission auditing and create unexpected access paths.Network Security Architecture
VPC Design and Segmentation Virtual Private Clouds (VPCs) provide network isolation for AWS resources, with separate VPCs per environment preventing network-level lateral movement between production and non-production workloads. Private subnets without direct internet access host sensitive workloads, with NAT gateways providing controlled egress for updates and external API access. Security Groups function as stateful, instance-level firewalls that should serve as the primary network access control mechanism. Security Group rules should follow least-privilege principles, allowing only required protocols and ports from specific source security groups or CIDR ranges. Network ACLs provide stateless, subnet-level controls suitable for coarse-grained blocking of known malicious IP ranges. PrivateLink and VPC Endpoints AWS PrivateLink and VPC Interface Endpoints enable private connectivity to AWS services without traversing the public internet, reducing exposure and improving security posture. VPC endpoints for S3, DynamoDB, and other services eliminate the need for internet gateways or NAT gateways for AWS service access. Gateway endpoints for S3 and DynamoDB provide free, scalable private access, while interface endpoints support additional services through Elastic Network Interfaces in VPC subnets. Endpoint policies restrict which resources can be accessed through endpoints, preventing data exfiltration through unauthorized S3 buckets. Egress Control Blocking 0.0.0.0/0 egress where possible prevents data exfiltration and command-and-control communication. Centralized egress through proxy servers or AWS Network Firewall enables traffic inspection, domain filtering, and comprehensive logging of outbound connections. VPC Flow Logs capture network traffic metadata, enabling detection of unusual connection patterns, data exfiltration attempts, and lateral movement. Flow log analysis identifies security group misconfigurations and provides forensic evidence during incident investigations.Logging and Detection
CloudTrail Configuration CloudTrail organization trails capture API activity across all accounts and regions, providing comprehensive audit logs for security analysis and compliance. S3 object lock with governance or compliance mode prevents log deletion or modification, ensuring tamper-evident audit trails. CloudTrail Lake enables SQL-based querying of CloudTrail events, supporting threat hunting, compliance reporting, and security analytics without complex log processing pipelines. Event data stores with appropriate retention periods balance storage costs with investigative requirements. AWS Config for Configuration Management AWS Config continuously monitors resource configurations, detecting drift from desired states and providing configuration history for compliance and troubleshooting. Config rules evaluate resource configurations against security best practices, triggering alerts or automated remediation when non-compliant resources are detected. Aggregators consolidate Config data across accounts and regions, enabling centralized compliance monitoring and reporting. Configuration snapshots provide point-in-time views of infrastructure state for change analysis and incident investigation. GuardDuty Threat Detection GuardDuty analyzes CloudTrail events, VPC Flow Logs, and DNS logs to detect threats including compromised instances, reconnaissance activity, and data exfiltration attempts. Machine learning models identify anomalous behavior that suggests credential compromise or malicious activity. GuardDuty findings should integrate with incident response workflows, triggering automated containment for high-severity threats while routing lower-severity findings to security teams for investigation. Suppression rules reduce noise from expected activity while maintaining detection for genuine threats. Security Hub and Macie Security Hub aggregates findings from GuardDuty, Config, IAM Access Analyzer, and third-party security tools, providing centralized security posture visibility. Security standards like CIS AWS Foundations Benchmark and AWS Foundational Security Best Practices provide prescriptive security controls with automated compliance checking. Macie discovers and classifies sensitive data in S3 buckets, identifying PII, credentials, and other sensitive information that may be improperly stored or exposed. Automated sensitive data discovery enables data governance and compliance with privacy regulations.Data Protection
KMS Key Management AWS KMS Customer Managed Keys (CMKs) provide customer-controlled encryption key management with hardware-backed key storage and comprehensive audit logging. Key policies combined with IAM policies enable fine-grained access control, with separation of duties between key administrators and key users. Cross-account keys enable encrypted backups and disaster recovery across account boundaries while maintaining centralized key management. Automatic key rotation reduces risk from key compromise while maintaining backward compatibility for encrypted data. CloudHSM provides dedicated hardware security modules for workloads requiring FIPS 140-2 Level 3 validated cryptographic operations or customer-exclusive key storage. S3 Security Controls S3 Block Public Access provides account-level and bucket-level controls that prevent accidental public exposure of S3 data. These settings should be enabled by default with exceptions requiring explicit justification and approval. Bucket policies with condition keys likeaws:PrincipalOrgID restrict access to principals within the AWS Organization, preventing unauthorized cross-account access. S3 versioning with MFA Delete protects against accidental or malicious object deletion, requiring multi-factor authentication for permanent deletion operations.
S3 Object Lock provides WORM (Write Once Read Many) storage for compliance and data protection, preventing object deletion or modification for specified retention periods.
Container and Compute Security
EKS Security Amazon EKS clusters should integrate with IAM through OIDC providers, enabling IAM Roles for Service Accounts (IRSA) that provide pods with temporary AWS credentials scoped to specific permissions. This eliminates shared node IAM roles that grant excessive permissions to all pods on a node. Pod Security Admission (PSA) replaces deprecated Pod Security Policies, enforcing security standards that prevent privileged containers, host namespace access, and other risky configurations. Admission controllers validate and mutate pod specifications before deployment, enforcing organizational security policies. Private EKS API endpoints prevent public internet access to Kubernetes control planes, while node hardening through minimal AMIs, security patches, and runtime security tools reduces attack surface. ECS and Fargate ECS task roles provide containers with scoped IAM permissions, following least-privilege principles that grant only required AWS service access. Task definitions should specify read-only root filesystems where possible, preventing runtime modifications that could indicate compromise. Container image scanning identifies vulnerabilities in container images before deployment, while image signing with AWS Signer or third-party tools ensures that only approved images run in production. ECR image scanning integrates with CI/CD pipelines, blocking deployment of images with critical vulnerabilities. Lambda Security Lambda functions should use least-privilege IAM execution roles that grant only required permissions for function operation. VPC configuration should be used selectively, as VPC-attached functions incur cold start latency and require careful network configuration. Environment variable encryption with KMS protects sensitive configuration data, while function-level concurrency controls prevent resource exhaustion and unexpected costs from runaway executions. Lambda layers should be carefully managed to prevent supply chain attacks through malicious dependencies.Governance and Compliance
AWS Config Rules and Conformance Packs Config rules automate compliance checking against organizational security standards, with managed rules covering common security requirements and custom rules supporting organization-specific policies. Conformance Packs bundle related Config rules into compliance frameworks like PCI-DSS or HIPAA, simplifying compliance management. Remediation actions automatically correct non-compliant resources, reducing manual toil and ensuring consistent security posture. Remediation should be tested thoroughly to prevent unintended service disruptions. AWS Control Tower Control Tower provides landing zone automation that establishes multi-account AWS environments with pre-configured guardrails, account factory, and centralized logging. Guardrails implement preventive and detective controls through SCPs and Config rules, enforcing security baselines across all accounts. Account Factory enables self-service account provisioning with consistent security controls, while dashboard visibility provides centralized compliance monitoring across the organization.Conclusion
AWS security requires comprehensive strategies that leverage platform-native services while implementing defense-in-depth controls across identity, network, data, and compute layers. Security engineers design AWS environments that balance security requirements with operational efficiency, implementing automated guardrails that prevent misconfigurations while enabling developer productivity. Success requires treating AWS security as an ongoing program rather than a one-time configuration, with continuous monitoring, regular security assessments, and iterative improvement based on evolving threats and organizational requirements.References
- AWS Well-Architected Framework (Security Pillar)
- CIS AWS Foundations Benchmark
- AWS Security Hub Standards
- AWS Security Best Practices