Simon Willison’s Weblog

How an empty S3 bucket can make your AWS bill explode (via) Maciej Pocwierz accidentally created an S3 bucket with a name that was already used as a placeholder value in a widely used piece of software. They saw 100 million PUT requests to their new bucket in a single day, racking up a big bill since AWS charges $5/million PUTs.

It turns out AWS charge that same amount for PUTs that result in a 403 authentication error, a policy that extends even to "requester pays" buckets!

So, if you know someone's S3 bucket name you can DDoS their AWS bill just by flooding them with meaningless unauthenticated PUT requests.

AWS support refunded Maciej's bill as an exception here, but I'd like to see them reconsider this broken policy entirely.

Update from Jeff Barr:

We agree that customers should not have to pay for unauthorized requests that they did not initiate. We’ll have more to share on exactly how we’ll help prevent these charges shortly.

s3-credentials 0.16. I spent entirely too long this evening trying to figure out why files in my new supposedly public S3 bucket were unavailable to view. It turns out these days you need to set a PublicAccessBlockConfiguration of {"BlockPublicAcls": false, "IgnorePublicAcls": false, "BlockPublicPolicy": false, "RestrictPublicBuckets": false}.

The s3-credentials --create-bucket --public option now does that for you. I also added a s3-credentials debug-bucket name-of-bucket command to help figure out why a bucket isn't working as expected. # 5th April 2024, 5:35 am

S3 is files, but not a filesystem (via) Cal Paterson helps some concepts click into place for me: S3 imitates a file system but has a number of critical missing features, the most important of which is the lack of partial updates. Any time you want to modify even a few bytes in a file you have to upload and overwrite the entire thing. Almost every database system is dependent on partial updates to function, which is why there are so few databases that can use S3 directly as a backend storage mechanism. # 10th March 2024, 11:47 am

Slashing Data Transfer Costs in AWS by 99% (via) Brilliant trick by Daniel Kleinstein. If you have data in two availability zones in the same AWS region, transferring a TB will cost you $10 in ingress and $10 in egress at the inter-zone rates charged by AWS.

But... transferring data to an S3 bucket in that same region is free (aside from S3 storage costs). And buckets are available with free transfer to all availability zones in their region, which means that TB of data can be transferred between availability zones for mere cents of S3 storage costs provided you delete the data as soon as it’s transferred. # 15th January 2024, 10:22 pm