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Description

The following analytic detects failed authentication attempts during the Multi-Factor Authentication (MFA) challenge on a Google Cloud Platform (GCP) tenant. It uses Google Workspace login failure events to identify instances where MFA methods were challenged but not successfully completed. This activity is significant as it may indicate an adversary attempting to access an account with compromised credentials despite MFA protection. If confirmed malicious, this could lead to unauthorized access attempts, potentially compromising sensitive data and resources within the GCP environment.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-11
  • Author: Bhavin Patel, Mauricio Velazco, Splunk
  • ID: 345f7e1d-a3fe-4158-abd8-e630f9878323

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1586 Compromise Accounts Resource Development
T1586.003 Cloud Accounts Resource Development
T1078 Valid Accounts Defense Evasion, Persistence, Privilege Escalation, Initial Access
T1078.004 Cloud Accounts Defense Evasion, Persistence, Privilege Escalation, Initial Access
T1621 Multi-Factor Authentication Request Generation Credential Access
Kill Chain Phase
  • Weaponization
  • Exploitation
  • Installation
  • Delivery
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 `gws_reports_login` event.name=login_failure `gws_login_mfa_methods` 
| stats count min(_time) as firstTime max(_time) as lastTime by user, src_ip, login_challenge_method 
| `gcp_authentication_failed_during_mfa_challenge_filter`

Macros

The SPL above uses the following Macros:

:information_source: gcp_authentication_failed_during_mfa_challenge_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • user
  • src_ip
  • login_challenge_method
  • event.parameters{}.multiValue{}

How To Implement

You must install the latest version of Splunk Add-on for Google Workspace from Splunkbase (https://splunkbase.splunk.com/app/5556) which allows Splunk administrators to collect Google Workspace event data in Splunk using Google Workspace APIs. Specifically, this analytic leverages the User log events.

Known False Positives

Legitimate users may miss to reply the MFA challenge within the time window or deny it by mistake.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
54.0 60 90 User $user$ failed to pass MFA challenge

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3