A metric filter and alarm should exist for console authentication failures
Description
Real-time monitoring of API calls can be achieved by directing CloudTrail logs to CloudWatch logs and establishing corresponding metric filters and alarms. It is recommended that a metric filter and alarm be established for failed console authentication attempts.
Rationale
Monitoring failed console logins may decrease lead time to detect an attempt to brute force a credential, and may provide an indicator, such as source IP, that can be used in other event correlation.
Perform the following to set up the metric filter, alarm, SNS topic, and subscription:
From the command line
Retrieve cloudtrail log group name
aws cloudtrail describe-trails
Create a metric filter based on the filter pattern provided, which checks for IAM policy changes and the <cloudtrail_log_group_name>
.
aws logs put-metric-filter --log-group-name <cloudtrail_log_group_name> --filter-name `<console_signin_failure_metric>` --metric-transformations metricName= `<console_signin_failure_metric>`,metricNamespace='CISBenchmark',metricValue=1 --filter-pattern '{ ($.eventName = ConsoleLogin) && ($.errorMessage = "Failed authentication") }'
- Ensure CloudTrail is set to
multi-region
and isLogging
is set True
. - Ensure there is at least one Event Selector with
IncludeManagementEvents
set to True
and ReadWriteType
set to All
.
Note: You can choose your own metricName
and metricNamespace
strings. Use the same metricNamespace
for all Foundations Benchmark metrics to group them together.
Create an SNS topic that the alarm notifies.
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.
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.
Create an alarm that is associated with the CloudWatch logs metric filter created in step 1 and the SNS topic created in step 2.
aws cloudwatch put-metric-alarm --alarm-name `<console_signin_failure_alarm>` --metric-name `<console_signin_failure_metric>` --statistic Sum --period 300 --threshold 1 --comparison-operator GreaterThanOrEqualToThreshold --evaluation-periods 1 --namespace 'CISBenchmark' --alarm-actions <sns_topic_arn>
References
- https://docs.aws.amazon.com/awscloudtrail/latest/userguide/receive-cloudtrail-log-files-from-multiple-regions.html
- https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudwatch-alarms-for-cloudtrail.html
- https://docs.aws.amazon.com/sns/latest/dg/SubscribeTopic.html
Configuring log metric filter and alarm on multi-region (global) CloudTrail logs provides the following benefits:
- 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.