cis-aws-foundations-5-10

name	cis-aws-foundations-5.10
description	Ensure security group changes are monitored
category	cis-monitoring
version	7.0.0
author	cyberstrike-official
tags	["cis","aws","monitoring","cloudwatch","cloudtrail","metric-filters","alarms","security-groups","vpc"]
cis_id	5.10
cis_benchmark	CIS AWS Foundations Benchmark v7.0.0
tech_stack	["aws"]
cwe_ids	[]
chains_with	["cis-aws-foundations-4.1","cis-aws-foundations-4.2"]
prerequisites	[]
severity_boost	{}

Ensure security group changes are monitored

Description

Real-time monitoring of API calls can be achieved by directing CloudTrail Logs to CloudWatch Logs or an external Security Information and Event Management (SIEM) environment, and establishing corresponding metric filters and alarms.

Security groups are stateful packet filters that control ingress and egress traffic within a VPC.

It is recommended that a metric filter and alarm be established to detect changes to security groups.

Rationale

CloudWatch is an AWS native service that allows you to observe and monitor resources and applications. CloudTrail logs can also be sent to an external Security Information and Event Management (SIEM) environment for monitoring and alerting.

Monitoring changes to security groups will help ensure that resources and services are not unintentionally exposed.

Impact

This may require additional 'tuning' to eliminate false positives and filter out expected activity so that anomalies are easier to detect.

Audit Procedure

Using AWS CLI

If you are using CloudTrail trails and CloudWatch, perform the following to ensure that there is at least one active multi-region CloudTrail trail with the prescribed metric filters and alarms configured:

1. Identify the log group name that is configured for use with the active multi-region CloudTrail trail:

• List all CloudTrail trails:

aws cloudtrail describe-trails

• Identify multi-region CloudTrail trails: Trails with "IsMultiRegionTrail" set to true

• Note the value associated with "Name":<trail-name>

• Note the <trail-log-group-name> within the value associated with "CloudWatchLogsLogGroupArn"

  • Example: arn:aws:logs:<region>:<account-id>:log-group:<trail-log-group-name>:*

• Ensure the identified multi-region CloudTrail trail is active:

aws cloudtrail get-trail-status --name <trail-name>

• Ensure IsLogging is set to TRUE

• Ensure the identified multi-region CloudTrail trail captures all management events:

aws cloudtrail get-event-selectors --trail-name <trail-name>

• Ensure there is at least one event selector for a trail with set to and set to