AWS CloudTrail now provides more granular control of data event logging with advanced event selectors. Data events provide visibility into the data plane resource operations performed on or within a resource. You can currently log data events on two resource types: Amazon S3 object-level API activity (e.g. GetObject, DeleteObject, and PutObject API operations), and AWS Lambda function execution activity (the Invoke API). With advanced event selectors, you can include or exclude values on fields such as EventSource, EventName, and ResourceARN. Advanced event selectors also support including or excluding values based on the first few characters (where applicable) providing more control over which CloudTrail data events you want to log and pay for. For example, you can log S3 DeleteObject APIs to narrow the CloudTrail events you receive to only destructive actions, enabling you to identify security issues while controlling costs. If you detect unauthorized activity, you can also take immediate action to restrict access.
Source:: Amazon AWS