from logs-aws.cloudtrail-*

// filter for DescribeInstances API calls
| where event.dataset == "aws.cloudtrail" and event.provider == "ec2.amazonaws.com" and event.action == "DescribeInstances"

// truncate the timestamp to a 30-second window
| eval target_time_window = DATE_TRUNC(30 seconds, @timestamp)

// keep only the relevant fields
| keep target_time_window, aws.cloudtrail.user_identity.arn, cloud.region

// count the number of unique regions and total API calls within the 30-second window
| stats region_count = count_distinct(cloud.region), window_count = count(*) by target_time_window, aws.cloudtrail.user_identity.arn

// filter for resources making DescribeInstances API calls in more than 10 regions within the 30-second window
| where region_count >= 10 and window_count >= 10

// sort the results by time windows in descending order
| sort target_time_window desc