The detection rule 'Detect AWS API Activities From Unapproved Accounts' is designed to monitor and identify successful AWS CloudTrail activities initiated by user accounts not sanctioned in approved lists. The core mechanism involves analyzing CloudTrail logs, specifically looking for events with an `errorCode` of success, and filtering out any users present in the identity lookup and a specific CSV file listing service accounts. The output of this detection query includes the count of events, as well as the timestamps of the first and last recorded instances of activity for each user or service. The rule is marked as deprecated due to the complexities involved in the dynamic management of the approved account list. The implementation necessitates the use of the AWS App for Splunk and appropriate input configurations, along with a periodic update process for validating service accounts. Additional context fields are available for notable events, but are noted to be unsupported in ES Incident Review, requiring config adjustments for visibility. False positives may occur when legitimate users or service accounts are mistakenly flagged due to their absence from the lookup tables, prompting updates to those lists to maintain accurate monitoring.