New s3 bucket, filling with files before anything was connected

Question

I have a new s3 bucket I'm setting up to act as storage for CrushFTP. Prior to setting up any connection to this new bucket it started filling with files in the screenshot below. I'm pretty new to s3 configuration but how can I tell where these are coming from? I have a bucket policy defined to allow logging and for an IAM account that s3 uses to PUT and GET and other permissions needed for access. No other account is allowed by the policy as a defined it other than me, the owner. The data in this seems to be basic info about the bucket and my account accessing it. Could it be logging?

https://i.imgur.com/vrg8sfx.png

Accepted Answer

Based on the screenshot and filename format, these look like S3 server access logging logs.

Server access logging is useful for security, audit, object requests and understanding your AWS costs.
When you set up logging on your bucket, it is enabled at the bucket level and logs to a configured destination bucket.  It is best practice to log to a **different** bucket than to the one you are monitoring otherwise you will end up in an infinite loop since each time you write a new log file it will be seen as a new request and create another new log file.
This can result in higher storage costs.

Would recommend verifying your server access logging configuration and ensuring they are directing to a different bucket.

For details, see https://docs.aws.amazon.com/AmazonS3/latest/userguide/ServerLogs.html
https://aws.amazon.com/premiumsupport/knowledge-center/s3-server-access-logs-same-bucket/

New s3 bucket, filling with files before anything was connected

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