Profile Applicability: Level 1


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 unauthorized API calls. 


Rationale: 

Monitoring unauthorized API calls will help reveal application errors and may reduce time to detect malicious activity. 


Audit: 

Perform the following to ensure that there is at least one active multi-region CloudTrail with prescribed metric filters and alarms configured: 

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

List all CloudTrails: aws cloudtrail describe-trails 

Identify Multi region Cloudtrails: Trails with "IsMultiRegionTrail" set to true 

From value associated with CloudWatchLogsLogGroupArn note 

2. Get a list of all associated metric filters for this : aws logs describe-metric-filters --log-group-name "" 

3. Ensure the output from the above command contains the following: "filterPattern": "{ ($.errorCode = "*UnauthorizedOperation") || ($.errorCode = "AccessDenied*") }" 

4. Note the  value associated with the filterPattern found in step 3. 

5. Get a list of CloudWatch alarms and filter on the captured in step 4. aws cloudwatch describe-alarms --query 'MetricAlarms[?MetricName== ``]' 

6. Note the AlarmActions value - this will provide the SNS topic ARN value. 

7. Ensure there is at least one active subscriber to the SNS topic 

aws sns list-subscriptions-by-topic --topic-arn 

at least one subscription should have "SubscriptionArn" with valid aws ARN. 


Remediation:

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  taken from audit step 1. 

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

2. Create an SNS topic that the alarm will notify 

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

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

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

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


References: 

1. https://aws.amazon.com/sns/ 

2. CCE-79186-3 

3. https://docs.aws.amazon.com/awscloudtrail/latest/userguide/receive-cloudtraillog-files-from-multiple-regions.html 

4. https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudwatch-alarmsfor-cloudtrail.html 

5. 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

CIS Controls:

6.5 Central Log Management 

    Ensure that appropriate logs are being aggregated to a central log management system for analysis and review. 

6.7 Regularly Review Logs 

    On a regular basis, review logs to identify anomalies or abnormal events.