AWS IAM S3Browser User or AccessKey Creation — Sigma Rule

Rule metadata and linked tags

Author: daniel.bohannon@permiso.io (@danielhbohannon). Source status: test; severity: high. Source dates: 2023-05-17 / not supplied.

{
  "product": "aws",
  "service": "cloudtrail"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: c566f779298d219eb9733ec7db1e554ff269f748f71b3fffd4eb9ff09adf53fe

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: AWS IAM S3Browser User or AccessKey Creation
id: db014773-d9d9-4792-91e5-133337c0ffee
status: test
description: Detects S3 Browser utility creating IAM User or AccessKey.
references:
    - https://permiso.io/blog/s/unmasking-guivil-new-cloud-threat-actor
author: daniel.bohannon@permiso.io (@danielhbohannon)
date: 2023-05-17
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.initial-access
    - attack.stealth
    - attack.t1059.009
    - attack.t1078.004
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: 'iam.amazonaws.com'
        eventName:
            - 'CreateUser'
            - 'CreateAccessKey'
        userAgent|contains: 'S3 Browser'
    condition: selection
falsepositives:
    - Valid usage of S3 Browser for IAM User and/or AccessKey creation
level: high

Original YAML and metadata in JSON

False positives

• Valid usage of S3 Browser for IAM User and/or AccessKey creation

Source references

• https://permiso.io/blog/s/unmasking-guivil-new-cloud-threat-actor