AWS IAM S3Browser LoginProfile 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: 981a9406ac25d4b00b2dfd446c87a14b3f22cc03f54f03c7b6229a3ac507c371

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 LoginProfile Creation
id: db014773-b1d3-46bd-ba26-133337c0ffee
status: test
description: Detects S3 Browser utility performing reconnaissance looking for existing IAM Users without a LoginProfile defined then (when found) creating a LoginProfile.
references:
    - https://permiso.io/blog/s/unmasking-guivil-new-cloud-threat-actor
author: daniel.bohannon@permiso.io (@danielhbohannon)
date: 2023-05-17
tags:
    - attack.execution
    - attack.persistence
    - attack.initial-access
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1059.009
    - attack.t1078.004
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: 'iam.amazonaws.com'
        eventName:
            - 'GetLoginProfile'
            - 'CreateLoginProfile'
        userAgent|contains: 'S3 Browser'
    condition: selection
falsepositives:
    - Valid usage of S3 Browser for IAM LoginProfile listing and/or creation
level: high

Original YAML and metadata in JSON

False positives

• Valid usage of S3 Browser for IAM LoginProfile listing and/or creation

Source references

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