This is both a bad tech and a security thing, but this was the paragraph that caught my eye:
We now understand why my S3 bucket was bombarded with millions of requests and why I ended up with a huge S3 bill. At that point, I had one more idea I wanted to explore. If all those misconfigured systems were attempting to back up their data into my S3 bucket, why not just let them do so? I opened my bucket for public writes and collected over 10GB of data within less than 30 seconds. Of course, I can’t disclose whose data it was. But it left me amazed at how an innocent configuration oversight could lead to a dangerous data leak!
The tl;dr is that even if you reject unauthorized requests for your S3 bucket, AWS will still bill you for them. And also, if you accept those requests, you get a lot of data you probably shouldn't have.