Sometimes a Bucket Tells You More Than It Should

3 min read

How It Started

During one of my regular bug-hunting sessions, I was exploring a staging environment of a travel platform.

Staging environments are interesting.

They often mirror production closely enough to be useful for developers.

Sometimes…

they're also a little less strict when it comes to security.

So I started looking around.

An Interesting Response

While browsing one of the application's subdomains, I noticed something unusual.

Instead of returning a normal webpage…

the server responded with an XML document.

At first, it looked harmless.

But after taking a closer look, I realized it wasn't just XML.

It was a storage bucket listing.

What I Found

Without any authentication, the bucket exposed information about the files it contained.

The response revealed details such as:

• Object names
• Upload timestamps
• File sizes
• Metadata associated with stored objects

Even more interesting…

the listed image objects could be opened directly in the browser.

No login.

No authentication.

Just a direct request.

Why This Matters

Cloud storage is commonly used for hosting images, documents, backups, and application assets.

Sometimes these files are intentionally public.

Sometimes…

the bucket itself is unintentionally left open.

Even if the exposed objects aren't sensitive, allowing anyone to enumerate the contents provides valuable reconnaissance.

An attacker now has visibility into:

• File naming conventions
• Storage structure
• Deployment patterns
• Publicly accessible assets

Information that was never meant to be part of the application's public interface.

The Bigger Lesson

Cloud misconfigurations remain one of the most common security issues.

Not because cloud platforms are insecure —

but because a single permission can change an entire storage bucket from private to public.

Security isn't only about encrypting data.

It's also about making sure only the right people can discover it in the first place.

Final Thoughts

This wasn't about bypassing authentication.

There wasn't any authentication to bypass.

It was simply a case of a cloud storage bucket exposing more information than intended.

Sometimes the best reconnaissance doesn't come from scanners or exploits.

Sometimes…

the application introduces you to its infrastructure all by itself.

Status: Duplicate

Happy Hunting 🐞

— sYz