Detection rules › Sigma

AWS IAM S3Browser LoginProfile Creation

Status
test
Severity
high
Log source
product aws, service cloudtrail
Author
daniel.bohannon@permiso.io (@danielhbohannon)
Source
github.com/SigmaHQ/sigma

Detects S3 Browser utility performing reconnaissance looking for existing IAM Users without a LoginProfile defined then (when found) creating a LoginProfile.

MITRE ATT&CK coverage

Event coverage

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Rule body yaml

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

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    eventSource: 'iam.amazonaws.com'
    eventName:
        - 'GetLoginProfile'
        - 'CreateLoginProfile'
    userAgent|contains: 'S3 Browser'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
eventNameeq
  • CreateLoginProfile
  • GetLoginProfile
eventSourceeq
  • iam.amazonaws.com
userAgentmatch
  • S3 Browser