Does AWS Athena not require any permissions to query an S3 Bucket?

Hi community,

I am currently working with Athena to query my data stored in an S3 bucket encrypted by a customer managed key. After I created the Athena workgroup and Athena database, I ran the query to create the table. And it went really smooth without any errors. Even after I ran query "select * from table", I received the results as I expected. I did not make any policy change to my key or bucket. Doe this mean Athena does not need to be granted any permissions to query S3? How is this secure? My Bucket is encrypted and the Athena can just query it freely. I do find it a little counter-intuitive. What should I do to make it securer? Please let me know your thoughts on this issue. Thanks!