#!/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.
#
# Remediation:
#
#   https://d1.awsstatic.com/whitepapers/compliance/AWS_CIS_Foundations_Benchmark.pdf
#
#   aws logs put-metric-filter \
#     --region us-east-1 \
#     --log-group-name CloudTrail/CloudWatchLogGroup \
#     --filter-name NetworkACLConfigChanges \
#     --filter-pattern '{ ($.eventName = CreateNetworkAcl) || ($.eventName = CreateNetworkAclEntry) || ($.eventName = DeleteNetworkAcl) || ($.eventName = DeleteNetworkAclEntry) || ($.eventName = ReplaceNetworkAclEntry) || ($.eventName = ReplaceNetworkAclAssociation) }' \
#     --metric-transformations metricName=NetworkAclEventCount,metricNamespace=CloudTrailMetrics,metricValue=1
#
#   aws cloudwatch put-metric-alarm \
#     --region us-east-1 \
#     --alarm-name NetworkACLConfigChangesAlarm \
#     --alarm-description "Triggered by AWS Network ACL(s) config changes." \
#     --metric-name NetworkAclEventCount \
#     --namespace CloudTrailMetrics \
#     --statistic Sum \
#     --comparison-operator GreaterThanOrEqualToThreshold \
#     --evaluation-periods 1 \
#     --period 300 \
#     --threshold 1 \
#     --actions-enabled \
#     --alarm-actions arn:aws:sns:us-east-1:123456789012:CloudWatchAlarmTopic

CHECK_ID_check311="3.11"
CHECK_TITLE_check311="[check311] Ensure a log metric filter and alarm exist for changes to Network Access Control Lists (NACL)"
CHECK_SCORED_check311="SCORED"
CHECK_TYPE_check311="LEVEL2"
CHECK_SEVERITY_check311="Medium"
CHECK_ASFF_TYPE_check311="Software and Configuration Checks/Industry and Regulatory Standards/CIS AWS Foundations Benchmark"
CHECK_ASFF_RESOURCE_TYPE_check311="AwsCloudTrailTrail"
CHECK_ALTERNATE_check311="check311"
CHECK_SERVICENAME_check311="vpc"
CHECK_RISK_check311='Monitoring unauthorized API calls will help reveal application errors and may reduce time to detect malicious activity.'
CHECK_REMEDIATION_check311='It is recommended that a metric filter and alarm be established for unauthorized requests.'
CHECK_DOC_check311='https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudwatch-alarms-for-cloudtrail.html'
CHECK_CAF_EPIC_check311='Logging and Monitoring'

check311(){
  check3x '\$\.eventName\s*=\s*CreateNetworkAcl.+\$\.eventName\s*=\s*CreateNetworkAclEntry.+\$\.eventName\s*=\s*DeleteNetworkAcl.+\$\.eventName\s*=\s*DeleteNetworkAclEntry.+\$\.eventName\s*=\s*ReplaceNetworkAclEntry.+\$\.eventName\s*=\s*ReplaceNetworkAclAssociation'
}