#!/usr/bin/env bash

# Prowler - the handy cloud security tool (c) by Toni de la Fuente
#
# This Prowler check is licensed under a
# Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
#
# You should have received a copy of the license along with this
# work. If not, see <http://creativecommons.org/licenses/by-nc-sa/4.0/>.
#
# 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 SecurityGroupConfigChanges \
#     --filter-pattern '{ ($.eventName = AuthorizeSecurityGroupIngress) || ($.eventName = AuthorizeSecurityGroupEgress) || ($.eventName = RevokeSecurityGroupIngress) || ($.eventName = RevokeSecurityGroupEgress) || ($.eventName = CreateSecurityGroup) || ($.eventName = DeleteSecurityGroup) }' \
#     --metric-transformations metricName=SecurityGroupEventCount,metricNamespace=CloudTrailMetrics,metricValue=1
#
#   aws cloudwatch put-metric-alarm \
#     --region us-east-1 \
#     --alarm-name SecurityGroupConfigChangesAlarm \
#     --alarm-description "Triggered by AWS security group(s) config changes." \
#     --metric-name SecurityGroupEventCount \
#     --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_check310="3.10"
CHECK_TITLE_check310="[check310] Ensure a log metric filter and alarm exist for security group changes (Scored)"
CHECK_SCORED_check310="SCORED"
CHECK_TYPE_check310="LEVEL2"
CHECK_SEVERITY_check310="Medium"
CHECK_ASFF_TYPE_check310="Software and Configuration Checks/Industry and Regulatory Standards/CIS AWS Foundations Benchmark"
CHECK_ASFF_RESOURCE_TYPE_check310="AwsCloudTrailTrail"
CHECK_ALTERNATE_check310="check310"
CHECK_SERVICENAME_check310="ec2"
CHECK_RISK_check310='Monitoring unauthorized API calls will help reveal application errors and may reduce time to detect malicious activity.'
CHECK_REMEDIATION_check310='It is recommended that a metric filter and alarm be established for unauthorized requests.'
CHECK_DOC_check310='https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudwatch-alarms-for-cloudtrail.html'
CHECK_CAF_EPIC_check310='Logging and Monitoring'

check310(){
  check3x '\$\.eventName\s*=\s*AuthorizeSecurityGroupIngress.+\$\.eventName\s*=\s*AuthorizeSecurityGroupEgress.+\$\.eventName\s*=\s*RevokeSecurityGroupIngress.+\$\.eventName\s*=\s*RevokeSecurityGroupEgress.+\$\.eventName\s*=\s*CreateSecurityGroup.+\$\.eventName\s*=\s*DeleteSecurityGroup'
}