Misconfigured S3 Bucket Exposed Data

A public website referenced an S3 bucket that was also used to store internal migration artifacts. A shared archive in that bucket contained a script with embedded credentials, which allowed escalation and retrieval of private exports. This post explains what went wrong, how to mitigate it, and points your team to a free lab where they can safely practice the discovery and remediation steps.

What happened

• Public site assets and internal files were stored in the same S3 bucket.
• A migration archive in a public folder contained a script with embedded credentials.
• Those credentials allowed the investigator to access additional folders and download sensitive exports (PII and project artifacts).
• Root causes: poor separation of public vs private storage and hardcoded secrets.

Why this matters

• Even a short-lived public exposure can be discovered and harvested by automated scanners.
• Mixing public website storage with backups or migration exports creates a single point of failure.
• Hardcoded keys in files or archives are effectively permanent secrets unless rotated quickly.

How to reduce risk

• Separate public and private storage. Public website buckets only; private buckets for backups and migration data.
• No hardcoded secrets. Use secret management (AWS Secrets Manager, Parameter Store) and short-lived roles.
• Default deny & monitor. Enable S3 Block Public Access for private buckets, turn on CloudTrail and S3 logging, and alert on unusual access.
• Automate scanning. Add secret scanning to CI and periodic checks for new public objects.

Want to practice safely?

If your team wants hands-on practice with the exact scenario (safe, legal, and free), try the lab at Pwned Labs:

https://pwnedlabs.io/labs/aws-s3-enumeration-basics

This lab walks you through the discovery and remediation steps in a controlled environment — perfect for training developers, ops, and security teams.

Final thought

This is an operational failure more than a technical one: treat cloud storage and secrets as sensitive by default. Separate public assets from internal artifacts, stop embedding credentials in shipped files, and automate detection — those three changes remove the easiest attack vectors.