Ensure a log metric filter and alarm exist for IAM policy changes

Perform the following to setup the metric filter, alarm, SNS topic, and subscription:

1. Create a metric filter based on filter pattern provided which checks for unauthorized API calls and the <cloudtrail_log_group_name> taken from audit step 1.

aws logs put-metric-filter --log-group-name <cloudtrail_log_group_name> --filter-name `<iam_changes_metric>` --metric-transformations metricName=`<iam_changes_metric>`,metricNamespace='CISBenchmark',metricValue=1 --filter-pattern '{($.eventName=DeleteGroupPolicy)||($.eventName=DeleteRolePolicy)||($.eventNa me=DeleteUserPolicy)||($.eventName=PutGroupPolicy)||($.eventName=PutRolePolic y)||($.eventName=PutUserPolicy)||($.eventName=CreatePolicy)||($.eventName=Del etePolicy)||($.eventName=CreatePolicyVersion)||($.eventName=DeletePolicyVersi on)||($.eventName=AttachRolePolicy)||($.eventName=DetachRolePolicy)||($.event Name=AttachUserPolicy)||($.eventName=DetachUserPolicy)||($.eventName=AttachGr oupPolicy)||($.eventName=DetachGroupPolicy)}'

Note You can choose your own metricName and metricNamespace strings. Using the same metricNamespace for all Foundations Benchmark metrics will group them together.

1. Create an SNS topic that the alarm will notify

aws sns create-topic --name <sns_topic_name>

Note you can execute this command once and then re-use the same topic for all monitoring alarms.

1. Create an SNS subscription to the topic created in step 2

aws sns subscribe --topic-arn <sns_topic_arn> --protocol <protocol_for_sns> --notification-endpoint <sns_subscription_endpoints>

Note you can execute this command once and then re-use the SNS subscription for all monitoring alarms.

1. Create an alarm that is associated with the CloudWatch Logs Metric Filter created in step 1 and an SNS topic created in step 2

aws cloudwatch put-metric-alarm --alarm-name `<iam_changes_alarm>` --metric-name `<iam_changes_metric>` --statistic Sum --period 300 --threshold 1 --comparison-operator GreaterThanOrEqualToThreshold --evaluation-periods 1 --namespace 'CISBenchmark' --alarm-actions <sns_topic_arn>

References

1. CCE-79189-7
2. https://docs.aws.amazon.com/awscloudtrail/latest/userguide/receive-cloudtrail-log-files-from-multiple-regions.html
3. https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudwatch-alarms-for-cloudtrail.html
4. https://docs.aws.amazon.com/sns/latest/dg/SubscribeTopic.html

Notes

Configuring log metric filter and alarm on Multi-region (global) CloudTrail

• ensures that activities from all regions (used as well as unused) are monitored
• ensures that activities on all supported global services are monitored
• ensures that all management events across all regions are monitored

Multiple Remediation Paths

AWS

SERVICE-WIDE (RECOMMENDED when many resources are affected): Deploy centralized guardrails and remediation using AWS Config Conformance Packs and (if applicable) AWS Organizations SCPs.

aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml

ASSET-LEVEL: Apply the resource-specific remediation steps above to only the affected assets.

PREVENTIVE: Add CI/CD policy checks (CloudFormation/Terraform validation) before deployment to prevent recurrence.

References for Service-Wide Patterns

• AWS Config Conformance Packs: https://docs.aws.amazon.com/config/latest/developerguide/conformance-packs.html
• AWS Organizations SCP examples: https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps_examples.html

Operational Rollout Workflow

Use this sequence to reduce risk and avoid repeated drift.

1. Contain at Service-Wide Scope First (Recommended)

• AWS: deploy/adjust organization conformance packs and policy guardrails.

aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml

2. Remediate Existing Affected Assets

• Execute the control-specific Console/CLI steps documented above for each flagged resource.
• Prioritize internet-exposed and production assets first.

3. Validate and Prevent Recurrence

• Re-scan after each remediation batch.
• Track exceptions with owner and expiry date.
• Add preventive checks in IaC/CI pipelines.