#!/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_extra73="7.3,7.03"
CHECK_TITLE_extra73="[extra73] Ensure there are no S3 buckets open to the Everyone or Any AWS user (Not Scored) (Not part of CIS benchmark)"
CHECK_SCORED_extra73="NOT_SCORED"
CHECK_TYPE_extra73="EXTRA"
CHECK_ALTERNATE_extra703="extra73"
CHECK_ALTERNATE_check73="extra73"
CHECK_ALTERNATE_check703="extra73"

# Improved and simplified check on Nov 18th 2018 due to a new bucket attribute
# called PolicyStatus, not available in all regions yet.

# extra73(){
#   ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' $PROFILE_OPT --region $REGION --output text)
#   for bucket in $ALL_BUCKETS_LIST; do
#     BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket $PROFILE_OPT --region $REGION --output text 2>&1)
#     if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
#       textFail "Access Denied Trying to Get Bucket Location for $bucket"
#       continue
#     fi
#     if [[ "None" == $BUCKET_LOCATION ]]; then
#       BUCKET_LOCATION="us-east-1"
#     fi
#     if [[ "EU" == $BUCKET_LOCATION ]]; then
#       BUCKET_LOCATION="eu-west-1"
#     fi
#
#     BUCKET_POLICY_STATUS=$($AWSCLI s3api get-bucket-policy-status --bucket $bucket --query PolicyStatus.IsPublic --output text | grep False)
#     if [[ $BUCKET_POLICY_STATUS ]];then
#       textFail "$BUCKET_LOCATION: $bucket bucket is Public!" "$BUCKET_LOCATION"
#     else
#       textPass "$BUCKET_LOCATION: $bucket bucket is not Public" "$BUCKET_LOCATION"
#     fi
#   done
# }


extra73(){
  textInfo "Looking for open S3 Buckets (ACLs and Policies) in all regions...  "
  ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' $PROFILE_OPT --output text)

  for bucket in $ALL_BUCKETS_LIST; do

    # 3 Different problems, let's show only 1 finding all together
    S3_FINDING_ALLUSERS_ACL="Ok"
    S3_FINDING_AUTHUSERS_ACL="Ok"
    S3_FINDING_POLICY="Ok"

    # LOCATION
    BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket $PROFILE_OPT --output text 2>&1)
    if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
      textFail "Access Denied Trying to Get Bucket Location for $bucket"
      continue
    fi
    if [[ "None" == $BUCKET_LOCATION ]]; then
      BUCKET_LOCATION="us-east-1"
    fi
    if [[ "EU" == $BUCKET_LOCATION ]]; then
      BUCKET_LOCATION="eu-west-1"
    fi

    # EXPLICIT DENY
    CHEK_FOR_EXPLICIT_DENY=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --output text 2>&1)
    if [[ $(echo "$CHEK_FOR_EXPLICIT_DENY" | grep AccessDenied) ]] ; then
      textInfo "$BUCKET_LOCATION: $bucket have an explicit Deny. Not possible to get ACL." "$bucket" "$BUCKET_LOCATION"
    else
      # PUBLIC BLOCK
      # https://docs.aws.amazon.com/cli/latest/reference/s3api/get-public-access-block.html
      BUCKET_PUBLIC_BLOCK=$($AWSCLI s3api get-public-access-block --bucket $bucket $PROFILE_OPT --region $BUCKET_LOCATION 2>/dev/null)
      BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL=$(echo $BUCKET_PUBLIC_BLOCK | jq .PublicAccessBlockConfiguration.BlockPublicAcls 2>/dev/null)
      BUCKET_PUBLIC_BLOCK_BLOCKPUBLICPOLICY=$(echo $BUCKET_PUBLIC_BLOCK | jq  .PublicAccessBlockConfiguration.BlockPublicPolicy 2>/dev/null)
      BUCKET_PUBLIC_BLOCK_BLOCKPUBLICACLS=$(echo $BUCKET_PUBLIC_BLOCK | jq  .PublicAccessBlockConfiguration.BlockPublicAcls 2>/dev/null)
      BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET=$(echo $BUCKET_PUBLIC_BLOCK | jq  .PublicAccessBlockConfiguration.RestrictPublicBuckets 2>/dev/null)
      if [[ $BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL == "true" ]] && [[ $BUCKET_PUBLIC_BLOCK_BLOCKPUBLICPOLICY == "true" ]] &&  [[ $BUCKET_PUBLIC_BLOCK_BLOCKPUBLICACLS == "true" ]] &&  [[ $BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET == "true" ]]; then
        textPass "$BUCKET_LOCATION: $bucket bucket is public blocked (public-access-block)" "$BUCKET_LOCATION"
      else
        ## ACL
        # check if AllUsers is in the ACL as Grantee
        CHECK_BUCKET_ALLUSERS_ACL=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AllUsers']" --output text |grep -v GRANTEE)
        CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_ALLUSERS_ACL)
        # check if AuthenticatedUsers is in the ACL as Grantee, they will have access with sigened URL only
        CHECK_BUCKET_AUTHUSERS_ACL=$($AWSCLI s3api get-bucket-acl $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AuthenticatedUsers']" --output text |grep -v GRANTEE)
        CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_AUTHUSERS_ACL)
        ## POLICY
        BUCKET_POLICY_STATUS=$($AWSCLI s3api get-bucket-policy-status $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket --query PolicyStatus.IsPublic --output text 2>/dev/null)
        if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL || $CHECK_BUCKET_ALLUSERS_POLICY == "True" ]]; then
          if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL ]] && [[ $BUCKET_PUBLIC_BLOCK_IGNOREPUBLICACL != "true" ]];then
            if [[ $CHECK_BUCKET_ALLUSERS_ACL ]];then
              S3_FINDING_ALLUSERS_ACL="bucket ACL is open to the Internet (Everyone) with permissions: $CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE"
            fi
            if [[ $CHECK_BUCKET_AUTHUSERS_ACL ]];then
              S3_FINDING_AUTHUSERS_ACL="bucket ACL is open to Authenticated users (Any AWS user) with permissions: $CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE"
            fi
          fi
          if [[ $BUCKET_PUBLIC_BLOCK_RESTRICPUBLICBUCKET != "true" ]] && [[ $BUCKET_POLICY_STATUS == "True" ]]; then
            # Here comes the magic: Find Statement Allow, Principal * and No Condition
            BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION=$($AWSCLI s3api get-bucket-policy $PROFILE_OPT --region $BUCKET_LOCATION --bucket $bucket \
              | jq '.Policy | fromjson' | jq '.Statement[] | select(.Effect=="Allow") | select(.Principal=="*" or .Principal.AWS=="*" or .Principal.CanonicalUser=="*") | select(has("Condition") | not)')
            if [[ $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION ]]; then
              # Let's do more magic and identify who can do what
              BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION_DETAILS=$(echo $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION \
                | jq '"[Principal: " + (.Principal|tostring) + " Action: " + (.Action|tostring) + "]"' )
              S3_FINDING_POLICY="bucket policy allow perform actions: $BUCKET_POLICY_ALLOW_ALL_WITHOUT_CONDITION_DETAILS"
            else
              textPass "$BUCKET_LOCATION: $bucket bucket policy with conditions" "$BUCKET_LOCATION"
            fi
          fi
        else
          textPass "$BUCKET_LOCATION: $bucket bucket is not open" "$bucket" "$BUCKET_LOCATION"
        fi
      fi
    fi
    if [[ $S3_FINDING_ALLUSERS_ACL != "Ok" ]] || [[ $S3_FINDING_AUTHUSERS_ACL != "Ok" ]] || [[ $S3_FINDING_POLICY != "Ok" ]] ; then
        textFail "$BUCKET_LOCATION: (bucket: $bucket) ALLUSERS_ACL: $S3_FINDING_ALLUSERS_ACL | AUTHUSERS_ACL: $S3_FINDING_AUTHUSERS_ACL | BUCKET_POLICY: $S3_FINDING_POLICY" "$BUCKET_LOCATION"
    fi
  done
}

# Then implementation below makes pararel checks but can reach AWS API limits
# and eventually doesn't work as expected

# extra73(){
#   textTitle "$ID73" "$TITLE73" "NOT_SCORED" "EXTRA"
#   textNotice "Looking for open S3 Buckets (ACLs and Policies) in all regions...  "
#   ALL_BUCKETS_LIST=$($AWSCLI s3api list-buckets --query 'Buckets[*].{Name:Name}' --profile $PROFILE --region $REGION --output text)
#   for bucket in $ALL_BUCKETS_LIST; do
#     extra73Thread $bucket &
#   done
#   wait
# }
# extra73Thread(){
#   bucket=$1
#   BUCKET_LOCATION=$($AWSCLI s3api get-bucket-location --bucket $bucket --profile $PROFILE --region $REGION --output text 2>&1)
#   if [[ $(echo "$BUCKET_LOCATION" | grep AccessDenied) ]]; then
#     textFail "Access Denied Trying to Get Bucket Location for $bucket"
#     return
#   fi
#   if [[ "None" == $BUCKET_LOCATION ]]; then
#     BUCKET_LOCATION="us-east-1"
#   fi
#   if [[ "EU" == $BUCKET_LOCATION ]]; then
#     BUCKET_LOCATION="eu-west-1"
#   fi
#   # check if AllUsers is in the ACL as Grantee
#   CHECK_BUCKET_ALLUSERS_ACL=$($AWSCLI s3api get-bucket-acl --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AllUsers']" --output text |grep -v GRANTEE)
#   CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_ALLUSERS_ACL)
#   # check if AuthenticatedUsers is in the ACL as Grantee, they will have access with sigened URL only
#   CHECK_BUCKET_AUTHUSERS_ACL=$($AWSCLI s3api get-bucket-acl --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --query "Grants[?Grantee.URI == 'http://acs.amazonaws.com/groups/global/AuthenticatedUsers']" --output text |grep -v GRANTEE)
#   CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE=$(echo -ne $CHECK_BUCKET_AUTHUSERS_ACL)
#   # to prevent error NoSuchBucketPolicy first clean the output controlling stderr
#   TEMP_POLICY_FILE=$(mktemp -t prowler-${ACCOUNT_NUM}-${bucket}.policy.XXXXXXXXXX)
#   $AWSCLI s3api get-bucket-policy --profile $PROFILE --region $BUCKET_LOCATION --bucket $bucket --output text --query Policy > $TEMP_POLICY_FILE 2> /dev/null
#   # check if the S3 policy has Principal as *
#   CHECK_BUCKET_ALLUSERS_POLICY=$(cat $TEMP_POLICY_FILE | sed -e 's/[{}]/''/g' | awk -v k="text" '{n=split($0,a,","); for (i=1; i<=n; i++) print a[i]}'|awk '/Principal/ && !skip { print } { skip = /Deny/} '|grep ^\"Principal|grep \*)
#   if [[ $CHECK_BUCKET_ALLUSERS_ACL || $CHECK_BUCKET_AUTHUSERS_ACL || $CHECK_BUCKET_ALLUSERS_POLICY ]];then
#     if [[ $CHECK_BUCKET_ALLUSERS_ACL ]];then
#       textWarn "$BUCKET_LOCATION: $bucket bucket is open to the Internet (Everyone) with permissions: $CHECK_BUCKET_ALLUSERS_ACL_SINGLE_LINE" "$BUCKET_LOCATION"
#     fi
#     if [[ $CHECK_BUCKET_AUTHUSERS_ACL ]];then
#       textWarn "$BUCKET_LOCATION: $bucket bucket is open to Authenticated users (Any AWS user) with permissions: $CHECK_BUCKET_AUTHUSERS_ACL_SINGLE_LINE" "$BUCKET_LOCATION"
#     fi
#     if [[ $CHECK_BUCKET_ALLUSERS_POLICY ]];then
#       textWarn "$BUCKET_LOCATION: $bucket bucket policy \"may\" allow Anonymous users to perform actions (Principal: \"*\")" "$BUCKET_LOCATION"
#     fi
#   else
#     textOK "$BUCKET_LOCATION: $bucket bucket is not open" "$BUCKET_LOCATION"
#   fi
#   rm -fr $TEMP_POLICY_FILE
# }