prowler/checks/check_extra787

#!/usr/bin/env bash

# Prowler - the handy cloud security tool (copyright 2020) 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_extra787="7.87"
CHECK_TITLE_extra787="[extra787] Check connection and authentication for Internet exposed Elasticsearch/Kibana ports"
CHECK_SCORED_extra787="NOT_SCORED"
CHECK_CIS_LEVEL_extra787="EXTRA"
CHECK_SEVERITY_extra787="Critical"
CHECK_ASFF_RESOURCE_TYPE_extra787="AwsEc2Instance"
CHECK_ALTERNATE_check787="extra787"
CHECK_SERVICENAME_extra787="es"
CHECK_RISK_extra787='Internet exposed services increases the risk of unauthorised.'
CHECK_REMEDIATION_extra787='Placing an Amazon ES domain within a VPC enables secure communication between Amazon ES and other services within the VPC without the need for an internet gateway; NAT device; or VPN connection. All traffic remains securely within the AWS Cloud.'
CHECK_DOC_extra787='https://docs.aws.amazon.com/elasticsearch-service/latest/developerguide/es-vpc.html'
CHECK_CAF_EPIC_extra787='Infrastructure Security'

extra787(){
  # Prowler will try to access each ElasticSearch server to port:
  # 9200 API, 9300 Communcation and 5601 Kibana to figure out if authentication is enabled.
  # That is from the host where Prowler is running and will try to read indices or get kibana status
  ES_API_PORT="9200"
  ES_DATA_PORT="9300"
  ES_KIBANA_PORT="5601"

  for regx in $REGIONS; do
    # create a list of SG open to the world with port $ES_API_PORT or $ES_DATA_PORT or $ES_KIBANA_PORT
    SG_LIST=$($AWSCLI ec2 describe-security-groups $PROFILE_OPT --region $regx --output text \
      --query "SecurityGroups[?length(IpPermissions[?((FromPort==null && ToPort==null) || (FromPort<=\`$ES_API_PORT\` && ToPort>=\`$ES_API_PORT\`) || (FromPort<=\`$ES_DATA_PORT\` && ToPort>=\`$ES_DATA_PORT\`) || (FromPort<=\`$ES_KIBANA_PORT\` && ToPort>=\`$ES_KIBANA_PORT\`)) && (contains(IpRanges[].CidrIp, \`0.0.0.0/0\`) || contains(Ipv6Ranges[].CidrIpv6, \`::/0\`))]) > \`0\`].{GroupId:GroupId}" 2>&1)
    if [[ $(echo "$SG_LIST" | grep -E 'AccessDenied|UnauthorizedOperation|AuthorizationError') ]]; then
        textInfo "$regx: Access Denied trying to describe security groups" "$regx"
        continue
    fi
    # in case of open security groups goes through each one
    if [[ $SG_LIST ]];then
      for sg in $SG_LIST;do
        # temp file store the list of instances IDs and public IP address if found
        TEMP_EXTRA787_FILE=$(mktemp -t prowler-${ACCOUNT_NUM}-es-domain.EXTRA787.XXXXXXXXXX)
        # finds instances with that open security group attached and get its public ip address (if it has one)
        $AWSCLI $PROFILE_OPT --region $regx ec2 describe-instances --filters Name=instance.group-id,Values=$sg --query 'Reservations[*].Instances[*].[InstanceId,PublicIpAddress]' --output text > $TEMP_EXTRA787_FILE
        # in case of exposed instances it does access checks
        if [[ -s "$TEMP_EXTRA787_FILE" ]];then
          while read instance eip ; do
            if [[ "$eip" != "None" ]];then
              # check for Elasticsearch on port $ES_API_PORT, rest API HTTP.
              CHECH_HTTP_ES_API=$(curl -m 2 -s -w "%{http_code}" -o /dev/null -X GET "http://$eip:$ES_API_PORT/_cat/indices")
              httpStatus $CHECH_HTTP_ES_API
              if [[ $CHECH_HTTP_ES_API -eq "200" ]];then
                textFail "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Elasticsearch port $ES_API_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              else
                textInfo "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Elasticsearch port $ES_API_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              fi
              # check for port $ES_DATA_PORT TCP, this is the communication port, not:
              # test_tcp_connectivity is in include/os_detector
              # syntax is 'test_tcp_connectivity $HOST $PORT $TIMEOUT' (in seconds)
              CHECH_HTTP_ES_DATA=$(test_tcp_connectivity $eip $ES_DATA_PORT 2)
              # Using HTTP error codes here as well to reuse httpStatus function
              # codes for better handling, so 200 is open and 000 is not responding
              httpStatus $CHECH_HTTP_ES_DATA
              if [[ $CHECH_HTTP_ES_DATA -eq "200" ]];then
                textFail "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Elasticsearch port $ES_DATA_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              else
                textInfo "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Elasticsearch port $ES_DATA_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              fi
              # check for Kibana on port $ES_KIBANA_PORT
              CHECH_HTTP_ES_KIBANA=$(curl -m 2 -s -w "%{http_code}" -o /dev/null -X GET "http://$eip:$ES_KIBANA_PORT/api/status")
              httpStatus $CHECH_HTTP_ES_KIBANA
              if [[ $CHECH_AUTH_5601 -eq "200" ]];then
                textFail "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Kibana on port $ES_KIBANA_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              else
                textInfo "$regx: Found instance $instance with public IP $eip on Security Group: $sg with Kibana on port $ES_KIBANA_PORT response $SERVER_RESPONSE" "$regx" "$instance"
              fi
            else
              textInfo "$regx: Found instance $instance with private IP on Security Group: $sg" "$regx"
            fi
          done < <(cat $TEMP_EXTRA787_FILE)
        fi
        rm -rf $TEMP_EXTRA787_FILE
      done
    else
      textPass "$regx: No Security Groups found open to 0.0.0.0/0 for Elasticsearch/Kibana ports" "$regx"
    fi
  done
}