#!/usr/bin/env bash

# Prowler - the handy cloud security tool (copyright 2019) 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_extra743="7.43"
CHECK_TITLE_extra743="[extra743] Check if API Gateway has client certificate enabled to access your backend endpoint"
CHECK_SCORED_extra743="NOT_SCORED"
CHECK_CIS_LEVEL_extra743="EXTRA"
CHECK_SEVERITY_extra743="Medium"
CHECK_ASFF_RESOURCE_TYPE_extra743="AwsApiGatewayRestApi"
CHECK_ALTERNATE_check743="extra743"
CHECK_SERVICENAME_extra743="apigateway"
CHECK_RISK_extra743='Possible man in the middle attacks and other similar risks.'
CHECK_REMEDIATION_extra743='Enable client certificate. Mutual TLS is recommended and commonly used for business-to-business (B2B) applications. It’s used in standards such as Open Banking. API Gateway now provides integrated mutual TLS authentication at no additional cost.'
CHECK_DOC_extra743='https://aws.amazon.com/blogs/compute/introducing-mutual-tls-authentication-for-amazon-api-gateway/'
CHECK_CAF_EPIC_extra743='Data Protection'

extra743(){
  for regx in $REGIONS; do
    LIST_OF_REST_APIS=$($AWSCLI $PROFILE_OPT --region $regx apigateway get-rest-apis --query 'items[*].id' --output text 2>&1)
    if [[ $(echo "$LIST_OF_REST_APIS" | grep -E 'AccessDenied|UnauthorizedOperation|AuthorizationError') ]]; then
        textInfo "$regx: Access Denied trying to get rest APIs" "$regx"
        continue
    fi 
    if [[ $LIST_OF_REST_APIS ]];then
      for api in $LIST_OF_REST_APIS; do
        API_GW_NAME=$($AWSCLI apigateway get-rest-apis $PROFILE_OPT --region $regx --query "items[?id==\`$api\`].name" --output text)
        LIST_OF_STAGES=$($AWSCLI $PROFILE_OPT --region $regx apigateway get-stages --rest-api-id $api --query 'item[*].stageName' --output text)
        if [[ $LIST_OF_STAGES ]]; then
          for stage in $LIST_OF_STAGES; do
            CHECK_CERTIFICATE=$($AWSCLI $PROFILE_OPT --region $regx apigateway get-stages --rest-api-id $api --query "item[?stageName==\`$stage\`].clientCertificateId" --output text)
            if [[ $CHECK_CERTIFICATE ]]; then
                textPass "$regx: API Gateway $API_GW_NAME ID $api in $stage has client certificate enabled" "$regx" "$API_GW_NAME"
              else
                textFail "$regx: API Gateway $API_GW_NAME ID $api in $stage has not client certificate enabled" "$regx" "$API_GW_NAME"
            fi
          done
        fi
      done
    else
      textInfo "$regx: No API Gateways found" "$regx"
    fi
  done
}
