cis-aws-foundations-5-1

name	cis-aws-foundations-5.1
description	Ensure unauthorized API calls are monitored
category	cis-monitoring
version	7.0.0
author	cyberstrike-official
tags	["cis","aws","monitoring","cloudwatch","cloudtrail","metric-filters","alarms","unauthorized-api"]
cis_id	5.1
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 unauthorized API calls 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.

It is recommended that a metric filter and alarm be established for unauthorized API calls.

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 unauthorized API calls will help reduce the time it takes to detect malicious activity and can alert you to potential security incidents.

Impact

This alert may be triggered by normal read-only console activities that attempt to opportunistically gather optional information but gracefully fail if they lack the necessary permissions.

If an excessive number of alerts are generated, then an organization may wish to consider adding read access to the limited IAM user permissions solely to reduce the number of alerts.

In some cases, doing this may allow users to actually view some areas of the system; any additional access granted should be reviewed for alignment with the original limited IAM user intent.

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