HOW I OVERLOOKED THE PROBLEM AND SHOT MYSELF IN THE FOOT

Summary from the TLDR InfoSec newsletter

This author disabled and deleted Identity & Access Management (IAM) users before updating associated Terraform state and key policies while migrating from legacy IAM users to SSO in an AWS environment, inadvertently locking access to an AWS KMS key. Terraform applied changes but masked the fact that the EKS cluster continued to use the orphaned key, causing permission failures and locking out key management until AWS Support intervened. Security teams should ensure IAM and key-policy transitions are sequenced and validated, maintain Terraform state accuracy, and treat KMS keys as high-risk break-glass resources during cloud IAM migrations.