Detect New Open S3 Buckets over AWS CLI
The following analytic detects the creation of open/public S3 buckets via the AWS CLI. It leverages AWS CloudTrail logs to identify events where a user has set bucket permissions to allow access to…
Description
The following analytic detects the creation of open/public S3 buckets via the AWS CLI. It leverages AWS CloudTrail logs to identify events where a user has set bucket permissions to allow access to "AuthenticatedUsers" or "AllUsers." This activity is significant because open S3 buckets can expose sensitive data to unauthorized users, leading to data breaches. If confirmed malicious, an attacker could gain unauthorized access to potentially sensitive information stored in the S3 bucket, posing a significant security risk.
Detection logic
Detection requirements
- Platform
- IaaSOffice SuiteSaaS
The rule states no platform. This is derived from the ATT&CK technique it maps to.
- Log source category
- aws_cloudtrail
Known benign triggers
- It is possible that an AWS admin has legitimately created a public bucket for a specific purpose. AWS strongly advises against granting full control to the "All Users" group. Investigate and apply the necessary filters as needed.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| docs.aws.amazon.com/cli/latest/reference/s3api/create-bucket.html | Only this detection cites it |
From the source
- At source
- Open at source
- Upstream identifier
- 39c61d09-8b30-4154-922b-2d0a694ecc22
- Tagged by the source as
- Suspicious AWS S3 ActivitiesS3 BucketcloudSplunk CloudSplunk EnterpriseSplunk Enterprise Securitythreat
Licence
- Published under
- Apache License 2.0Read the licence
- Attribution
- Required
- Obtained under
- Apache-2.0Read the origin licence
Authorship
- Written by
- Published
- Oct 9, 2026
- Version
- 2