In the past decade, access management in AWS has undergone a fundamental transformation. What began as a simple model built for individual IAM users has now evolved into a scalable, enterprise-grade identity architecture aligned with Zero Trust principles and cloud-native best practices.
But this evolution hasn’t just been about new tools—it’s a response to a radically changed operational and threat landscape.
In this post, we’ll break down the phases of AWS Identity and Access Management (IAM), explore what has changed, and share best practices for managing permissions at scale in a multi-account AWS environment.
Phase One: IAM Users and Static Access
When AWS first launched, IAM was designed around static IAM users with long-lived credentials—access keys manually configured and distributed across environments.
While this model was initially practical for small teams or single-account setups, it quickly broke down at scale. Key issues included:
- Over-permissioned accounts with broad policies.
- Standing access that violated least-privilege principles.
- Credential sprawl and poor auditability.
- High operational overhead for rotation, termination, and incident response.
This architecture fundamentally lacked agility and visibility—especially for organizations scaling into multi-account, multi-region environments.
Phase Two: Roles, STS, and Federated Access
AWS introduced IAM roles and the Security Token Service (STS) to solve key limitations. Roles allowed temporary credentials to be assumed via trust policies, while STS enabled session-based access with defined time limits.
This paved the way for federated access, where companies could connect existing identity providers (IdPs) like Okta, Entra ID, or Google Workspace to AWS. Instead of managing users directly in AWS, they could federate identities and delegate permission assignment.
This significantly improved:
- Access lifecycle management, especially for joiners, movers, and leavers.
- Security posture, by reducing standing access.
- Auditability, with session logs and identity federation.
But managing roles and trust relationships across multiple AWS accounts still required complex, manual orchestration.
Phase Three: AWS Organizations and the Multi-Account Model
As AWS environments matured, organizations adopted a multi-account strategy—separating workloads, environments, and business units into individual accounts using AWS Organizations.
This model improved:
- Isolation and fault tolerance
- Compliance boundaries
- Cost attribution and governance
However, it also introduced new challenges: How do you consistently manage permissions across dozens (or hundreds) of AWS accounts?
IAM roles had to be manually duplicated and mapped across accounts, and governance often depended on spreadsheets and tribal knowledge. This complexity paved the way for a more centralized solution.
Phase Four: AWS IAM Identity Center (Formerly AWS SSO)
To solve the coordination problem, AWS introduced IAM Identity Center—an evolution of AWS SSO that enables centralized identity and access orchestration across AWS Organizations.
Key innovations include:
- Permission Sets: Templates that define access policies, mapped to roles in each account.
- Group-based Assignments: Access can be granted at the group level via an external IdP (e.g., Okta).
- Cross-account Visibility: Admins manage access centrally, while users log in via a unified dashboard.
- Short-lived Credentials: Role assumptions reduce the blast radius and improve auditability.
This marks a significant step toward identity as the control plane—a foundational principle in Zero Trust architectures.
Where We Are Now: Identity-Centric, Scalable, and Context-Aware
Today, the modern AWS access architecture follows a layered model:
- Identity Provider (IdP) – Okta, Entra ID, etc. as the source of identity truth.
- IAM Identity Center – Central hub for managing access policies and permissions.
- Permission Sets – Codified roles for just-in-time access across environments.
- AWS Organizations – Account structure for separation of duties and isolation.
Combined, this architecture reduces friction, enables faster onboarding, and significantly improves security posture. But it’s not without challenges.
Challenges in Practice
Despite the progress, many organizations still struggle with:
- Permission sprawl and over-provisioning: 99% of permissions go unused (Microsoft, 2023).
- Manual reviews: Access reviews remain spreadsheet-driven and error-prone.
- Delayed access: Teams wait hours (or days) for access to critical cloud resources.
- Limited automation: Many workflows are still hard-coded or dependent on human intervention.
- Cross-platform complexity: AWS IAM only addresses a piece of the broader access puzzle, leaving gaps across SaaS, databases, and on-prem systems.
The Next Step: Purpose-Built PAM for AWS
As AWS environments evolve, so too must the security strategies that protect them. With the shift from network-centric to identity-centric security models, PAM is no longer optional—it’s critical infrastructure.
AWS IAM has grown more granular and powerful, but also more complex. Managing least-privilege access across ephemeral workloads, cross-account roles, and dynamic developer environments requires more than built-in tooling. It requires a Privileged Access Management (PAM) solution designed specifically for AWS scale and context.
Best practices for modern PAM in AWS include:
- Just-in-Time (JIT) Access: Replace standing privileges with on-demand, time-bound access.
- Granular Resource Control: Go beyond account-level roles to manage access at the service, resource, and even action level.
- Policy Automation: Use identity attributes, environment tags, and workload metadata to drive dynamic access decisions.
- Continuous Access Reviews: Move away from periodic audits to real-time visibility and drift detection.
- Integrated Developer Workflows: Embed access into CI/CD pipelines and developer tools to minimize friction.
Modern PAM must not only secure AWS but also simplify operations and enhance developer agility.
Final Thoughts
AWS has made tremendous progress in modernizing identity and access management—but even with IAM Identity Center, achieving true least-privilege access requires a thoughtful, layered strategy.
Organizations that combine AWS-native tools with intelligent, AWS-aware PAM solutions will be best positioned to manage scale, reduce risk, and move fast without compromise.
Ready to simplify and secure AWS access across your cloud ecosystem? Let’s talk.
