Enabling S3 Object Lock on a bucket does not protect the objects already in it. This is how to build an audit evidence repository on AWS that survives the question auditors actually ask, covering retention modes you cannot undo, delete markers that hide protected versions, chain of custody, and the storage bill compliance mode makes permanent.
Cognito for sign-in, S3 for the files, and a demo that passes on the first try. The problems start after that. Prefix isolation, presigned URL lifetimes, KMS as a second gate, CloudTrail data events, and token revocation that actually ends a session.
Unused access findings tell you what AWS did not record activity for, which is not the same as what your workload does not need. Here are the four blind spots in the underlying data, and a deny-before-delete procedure that lets you trim IAM permissions with a one-call rollback.
Storing tenant IDs, leases and referencing packs is easy until someone asks who actually read them. Five failure families in property SaaS document storage, with the IAM policies, presigned URL mechanics, upload controls and deletion patterns that close each one.
A generated policy with no wildcards can still hand over your account. Here are the three failure shapes that survive human review, why the review step is the wrong place to put your defence, and how to build a ceiling that holds regardless of what the model writes.
Both give your pods short-lived AWS credentials, but they put the cluster-to-role relationship in completely different places. A practical comparison of EKS Pod Identity vs IRSA: where each one wins, where each refuses to run, the silent node-role fallback that hides broken wiring, and a decision procedure you can apply per workload.
A missing tenant filter doesn't throw an error, it returns a 200 with too many rows. This is how to build a multi-tenant workshop management platform on AWS where the isolation boundary sits below your application code: STS session tags feeding IAM conditions, DynamoDB leading keys, scoped S3 prefixes, forced PostgreSQL row-level security, and a control plane that verifies each new tenant is fenced before anyone logs in.
Most accounting-firm document vaults do not fail at the bucket. They fail at the edges: a download link that outlives the engagement, a KMS key policy as wide as the bucket policy, a retention lock that cannot be undone, and an audit trail nobody switched on. Six failure families, and the control that closes each.
Shared admin credentials work right up until someone resigns or an auditor asks who did what. Here's how to design client AWS account access around cross-account roles, unique external IDs and per-engineer attribution, so twenty accounts need zero shared keys and revocation is one action.
Before I quote AWS work, I run a read-only account health check: six passes covering identity, logging, region sprawl, infrastructure code, cost shape and support escalation. Here are the commands, the pass tests, and the findings that change the number.