AWS Console GetSigninToken Potential Abuse

Status: test
Severity: medium
Log source: product aws, service cloudtrail
Author: Chester Le Bron (@123Le_Bron)
Source: github.com/SigmaHQ/sigma

Detects potentially suspicious events involving "GetSigninToken". An adversary using the "aws_consoler" tool can leverage this console API to create temporary federated credential that help obfuscate which AWS credential is compromised (the original access key) and enables the adversary to pivot from the AWS CLI to console sessions without the need for MFA using the new access key issued in this request.

Known false positives

GetSigninToken events will occur when using AWS SSO portal to login and will generate false positives if you do not filter for the expected user agent(s), see filter. Non-SSO configured roles would be abnormal and should be investigated.

MITRE ATT&CK coverage

Tactic	Techniques
Lateral Movement	`T1021.007` Remote Services: Cloud Services `T1550.001` Use Alternate Authentication Material: Application Access Token

Telemetry coverage

Platform	Record / event type
AWS	CloudTrail event `GetSigninToken`: Retrieves a sign-in token used to grant console access to a federated user via the AWS federation endpoint.

Rules detecting the same action

These rules filter on the same operation.

AWS Console GetSigninToken Potential Abuse (Panther)
AWS EC2 Instance Console Login via Assumed Role (Elastic)
AWS Sign-In Token Created (Elastic)

Rule body

title: AWS Console GetSigninToken Potential Abuse
id: f8103686-e3e8-46f3-be72-65f7fcb4aa53
status: test
description: |
    Detects potentially suspicious events involving "GetSigninToken".
    An adversary using the "aws_consoler" tool can leverage this console API to create temporary federated credential that help obfuscate which AWS credential is compromised (the original access key) and enables the adversary to pivot from the AWS CLI to console sessions without the need for MFA using the new access key issued in this request.
references:
    - https://github.com/NetSPI/aws_consoler
    - https://www.crowdstrike.com/blog/analysis-of-intrusion-campaign-targeting-telecom-and-bpo-companies/
author: Chester Le Bron (@123Le_Bron)
date: 2024-02-26
tags:
    - attack.lateral-movement
    - attack.t1021.007
    - attack.t1550.001
logsource:
    product: aws
    service: cloudtrail
detection:
    selection:
        eventSource: 'signin.amazonaws.com'
        eventName: 'GetSigninToken'
    filter_main_console_ua:
        userAgent|contains: 'Jersey/${project.version}'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - GetSigninToken events will occur when using AWS SSO portal to login and will generate false positives if you do not filter for the expected user agent(s), see filter. Non-SSO configured roles would be abnormal and should be investigated.
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    eventSource: 'signin.amazonaws.com'
    eventName: 'GetSigninToken'

Stage 2: `not filter_main_console_ua`

filter_main_console_ua:
    userAgent|contains: 'Jersey/${project.version}'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`userAgent`	match	`Jersey/${project.version}`	`excludes:userAgent` `field:"userAgent" value:"Jersey/${project.version}"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`eventName`	eq	`GetSigninToken`	`field:"aws::eventName" kind:eq value:"GetSigninToken"`
`eventSource`	eq	`signin.amazonaws.com`	`field:"aws::eventSource" kind:eq value:"signin.amazonaws.com"`