Detection: Okta Multiple Failed MFA Requests For User

Updated Date: 2024-05-20 ID: 826dbaae-a1e6-4c8c-b384-d16898956e73 Author: Mauricio Velazco, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies multiple failed multi-factor authentication (MFA) requests for a single user within an Okta tenant. It triggers when more than 10 MFA attempts fail within 5 minutes, using Okta event logs to detect this pattern. This activity is significant as it may indicate an adversary attempting to bypass MFA by bombarding the user with repeated authentication requests, a technique used by threat actors like Lapsus and APT29. If confirmed malicious, this could lead to unauthorized access, potentially compromising sensitive information and systems.

1 `okta` eventType=user.authentication.auth_via_mfa outcome.result=FAILURE debugContext.debugData.factor!=PASSWORD_AS_FACTOR 
2| bucket _time span=5m 
3| stats count min(_time) as firstTime max(_time) as lastTime values(displayMessage) values(src_ip) as src_ip values(debugContext.debugData.factor) by _time src_user 
4| where count >= 10 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `okta_multiple_failed_mfa_requests_for_user_filter`

Data Source

Name Platform Sourcetype Source Supported App
Okta N/A 'OktaIM2:log' 'Okta' N/A

Macros Used

Name Value
okta eventtype=okta_log OR sourcetype = "OktaIM2:log"
okta_multiple_failed_mfa_requests_for_user_filter search *
okta_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
T1621 Multi-Factor Authentication Request Generation Credential Access
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
APT29
LAPSUS$
Scattered Spider

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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

The analytic leverages Okta OktaIm2 logs to be ingested using the Splunk Add-on for Okta Identity Cloud (https://splunkbase.splunk.com/app/6553).

Known False Positives

Multiple Failed MFA requests may also be a sign of authentication or application issues. Filter as needed and monitor for any unusual activity.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Multiple failed MFA requests for user $src_user$ from IP Address - $src_ip$ 42 60 70
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset Okta OktaIM2:log
Integration ✅ Passing Dataset Okta OktaIM2:log

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: 2