file where
event.dataset == "aws.cloudtrail" and
event.provider == "s3.amazonaws.com" and
event.action == "PutObject" and
event.outcome == "success" and
/* Apply regex to match patterns only after the bucket name */
aws.cloudtrail.resources.arn regex "arn:aws:s3:::[^/]+/.*?(ransom|lock|crypt|enc|readme|how_to_decrypt|decrypt_instructions|recovery|datarescue).*" and
not aws.cloudtrail.resources.arn regex ".*(AWSLogs|CloudTrail|access-logs).*"
Install detection rules in Elastic Security
Detect Potential AWS S3 Bucket Ransomware Note Uploaded in the Elastic Security detection engine by installing this rule into your Elastic Stack.
To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).