AWS IAM Anti-Patterns and How to Fix Them

IAM misconfigurations are one of the most common, and dangerous, mistakes in AWS. This guide outlines high-risk IAM anti-patterns, explains how they happen, and offers actionable fixes to enforce least privilege across your cloud environment.

⚠️ Common IAM Anti-Patterns

1. Overuse of AdministratorAccess

Assigning the AdministratorAccess managed policy to users, roles, or services grants full access to everything in the account. It is often used as a shortcut during testing, and then never removed.

Fix:

• Replace with scoped policies per role (e.g., S3Reader, LambdaDeployer)
• Use IAM Access Analyzer to detect excessive permissions

2. Wildcard Permissions

Permissions like "Action": "*" or "Resource": "*" are highly risky. They’re often used when teams aren’t sure what’s needed or want to “just get it working.”

Fix:

• Use AWS IAM Access Advisor or CloudTrail to narrow down required actions
• Start with read-only access and expand incrementally

3. Reusing IAM Users Across Apps

IAM users should never be hardcoded or shared across systems. They’re not meant for automation, roles and temporary credentials are.

Fix:

• Use IAM roles and federated access (e.g., OIDC, SAML)
• If user access is required, enable MFA and restrict by IP and service

4. Lack of Role Separation

Giving a single IAM role access to all infrastructure and services breaks separation of duties and creates security blind spots.

Fix:

• Create task-specific roles (e.g., ReadOnlyAuditor, CICDPipeline, EC2Lifecycle)
• Group permissions by resource type and action scope

5. No Monitoring or Logging of IAM Activity

If you can’t track IAM changes, you can’t audit them. SOC 2, HIPAA, and ISO require this visibility.

Fix:

• Enable CloudTrail across all regions
• Set CloudWatch alarms for IAM changes (e.g., AttachRolePolicy)
• Log and review AssumeRole usage via CloudTrail

✅ Best Practices for IAM Security

• Use least-privilege policies with specific actions and ARNs
• Rotate access keys or use temporary credentials (STS)
• Group users by roles, not by individual permissions
• Apply SCPs (Service Control Policies) in org-level environments
• Use tools like Parliament, Access Analyzer, or IAM Access Advisor regularly

🔗 Helpful Resources

• AWS IAM User Guide
• Parliament: IAM Policy Linter
• IAM Access Analyzer