Granular Permission Policy for AWS S3 (standalone software)

Situation

Assigning full AWS S3 access permission policy to IAM user is generally not recommended due to security considerations, 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": "*"
        }
        { 
            “Effect”: “Allow”, 
            “Action”: “sts:GetFederationToken”, 
            “Resource”: “*”, 
            “Condition”: {} 
        }
    ]
}