#!/usr/bin/env bash

# Prowler - the handy cloud security tool (copyright 2018) by Toni de la Fuente
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
# use this file except in compliance with the License. You may obtain a copy
# of the License at http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software distributed
# under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
# CONDITIONS OF ANY KIND, either express or implied. See the License for the
# specific language governing permissions and limitations under the License.
CHECK_ID_extra771="7.71"
CHECK_TITLE_extra771="[extra771] Check if S3 buckets have policies which allow WRITE access (Not Scored) (Not part of CIS benchmark)"
CHECK_SCORED_extra771="NOT_SCORED"
CHECK_TYPE_extra771="EXTRA"
CHECK_SEVERITY_extra771="Critical"
CHECK_ASFF_RESOURCE_TYPE_extra771="AwsS3Bucket"
CHECK_ALTERNATE_check771="extra771"

extra771(){
  LIST_OF_BUCKETS=$($AWSCLI s3api list-buckets $PROFILE_OPT --region $REGION --query Buckets[*].Name --output text|xargs -n1)
  if [[ $LIST_OF_BUCKETS ]]; then
    for bucket in $LIST_OF_BUCKETS;do
      BUCKET_POLICY_STATEMENTS=$($AWSCLI s3api $PROFILE_OPT get-bucket-policy --region $REGION --bucket $bucket --output json --query Policy 2>&1)
      if [[ $BUCKET_POLICY_STATEMENTS == *GetBucketPolicy* ]]; then
        textInfo "Bucket policy does not exist for bucket $bucket"
      else
        BUCKET_POLICY_BAD_STATEMENTS=$(echo $BUCKET_POLICY_STATEMENTS | jq --arg arn "arn:${AWS_PARTITION}:s3:::$bucket" 'fromjson | .Statement[]|select(.Effect=="Allow" and (((.Principal|type == "object") and .Principal.AWS == "*") or ((.Principal|type == "string") and .Principal == "*")) and (.Action|startswith("s3:Put") or startswith("s3:*")) and .Condition == null)')
        if [[ $BUCKET_POLICY_BAD_STATEMENTS != "" ]]; then
          textFail "Bucket $bucket allows public write: $BUCKET_POLICY_BAD_STATEMENTS"
        else
          textPass "Bucket $bucket has S3 bucket policy which does not allow public write access"
        fi
      fi
    done

  else
    textInfo "No S3 Buckets found"
  fi
}