Granular Permission Policy for AWS S3

Situation

Assigning of full S3 access permission policy to the IAM user is generally not recommended, so users are encouraged to use granular permission policies instead.

Solution

This granular policy includes the minimal set of permissions required to use all of the backup software’s functionality, including retention and immutability:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:ListBucket",
                "s3:GetBucketLocation",
                "s3:ListBucketMultipartUploads",
                "s3:ListBucketVersions",
                "s3:GetBucketObjectLockConfiguration",
                "s3:PutBucketObjectLockConfiguration"
            ],
            "Resource": "arn:aws:s3:::bucket_name"
        },
        {
            "Effect": "Allow",
            "Action": [
                "s3:AbortMultipartUpload",
                "s3:ListMultipartUploadParts",
                "s3:DeleteObject",
                "s3:DeleteObjectVersion",
                "s3:GetObject",
                "s3:GetObjectAcl",
                "s3:GetObjectVersion",
                "s3:GetObjectVersionAcl",
                "s3:PutObject",
                "s3:PutObjectAcl",
                "s3:PutObjectVersionAcl",
                "s3:RestoreObject"
            ],
            "Resource": "arn:aws:s3:::bucket_name/*"
        },
        {
            "Effect": "Allow",
            "Action": "s3:ListAllMyBuckets",
            "Resource": "*"
        }
    ]
}