The rule identifies a potential brute force attack or enumeration attempt on AWS S3 buckets, characterized by a high volume of failed S3 API operations (specifically those resulting in "AccessDenied" errors) from a single source and account within a short timeframe. This behavior may suggest intentions such as causing excessive billing to an AWS account, exhausting resources, or discovering valid S3 buckets by trying numerous operations—many of which can incur costs regardless of access rights. The detection logic aggregates failed requests to pinpoint unusual activity, raising an alert when a predefined threshold (e.g., more than 40 failed requests) is exceeded. The rule is particularly useful for monitoring both authenticated and anonymous requests, as attackers can often engage with S3 buckets indiscriminately, leading to significant financial and operational impacts. The investigation notes provided in the rule outline specific steps security teams can follow to assess the activity's context, investigate possible malicious intent, and respond appropriately to mitigate risks associated with AWS account compromise.