Detection: GCP Multiple Failed MFA Requests For User

Updated Date: 2026-05-13 ID: cbb3cb84-c06f-4393-adcc-5cb6195621f1 Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects multiple failed multi-factor authentication (MFA) requests for a single user within a Google Cloud Platform (GCP) tenant. It triggers when 10 or more MFA prompts fail within a 5-minute window, using Google Workspace login failure events. This behavior is significant as it may indicate an adversary attempting to bypass MFA by bombarding the user with repeated authentication requests. If confirmed malicious, this activity could lead to unauthorized access, allowing attackers to compromise accounts and potentially escalate privileges within the GCP environment.

Search

 1`gws_reports_login` event.name=login_failure `gws_login_mfa_methods`
 2  
 3| bucket span=5m _time
 4  
 5| stats dc(_raw) AS mfa_prompts values(user) AS user
 6    BY src_ip, login_challenge_method, _time
 7  
 8| where mfa_prompts >= 10
 9  
10| `gcp_multiple_failed_mfa_requests_for_user_filter`

Data Source

Name	Platform	Sourcetype	Source
Google Workspace	Other	`'gws:reports:login'`	`'google_workspace'`

Macros Used

Name	Value
gws_reports_login	`sourcetype=gws:reports:login`
gcp_multiple_failed_mfa_requests_for_user_filter	`search *`

gcp_multiple_failed_mfa_requests_for_user_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1078.004	Cloud Accounts	Initial Access
T1586.003	Cloud Accounts	Persistence
T1621	Multi-Factor Authentication Request Generation	Privilege Escalation

Exploitation

Delivery

Installation

Weaponization

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

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. We would also recommend tuning the detection by adjusting the window span and mfa_prompts threshold values according to your environment. Specifically, this analytic leverages the User log events.

Known False Positives

Multiple Failed MFA requests may also be a sign of authentication or application issues. Filter as needed.

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
Multiple Failed MFA requests for user $user$	user	user	50

Threat Objects

Field	Type
src_ip	ip_address

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`gws:reports:login`	`gws:reports:login`
Integration	✅ Passing	Dataset	`gws:reports:login`	`gws:reports:login`

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: GitHub | Version: 12