Detection: Okta Multiple Users Failing To Authenticate From Ip

Updated Date: 2024-05-28 ID: de365ffa-42f5-46b5-b43f-fa72290b8218 Author: Michael Haag, Mauricio Velazco, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies instances where more than 10 unique user accounts have failed to authenticate from a single IP address within a 5-minute window in an Okta tenant. This detection uses OktaIm2 logs ingested via the Splunk Add-on for Okta Identity Cloud. Such activity is significant as it may indicate brute-force attacks or password spraying attempts. If confirmed malicious, this behavior suggests an external entity is attempting to compromise multiple user accounts, potentially leading to unauthorized access to organizational resources and data breaches.

1 
2| tstats `security_content_summariesonly` count max(_time) as lastTime, min(_time) as firstTime dc(Authentication.user) as unique_accounts values(Authentication.signature) as signature values(Authentication.user) as user values(Authentication.app) as app values(Authentication.authentication_method) as authentication_method from datamodel=Authentication where Authentication.action="failure" AND Authentication.signature=user.session.start by _time span=5m Authentication.src sourcetype 
3| where unique_accounts > 9 
4| `drop_dm_object_name("Authentication")` 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `okta_multiple_users_failing_to_authenticate_from_ip_filter`

Data Source

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

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
okta_multiple_users_failing_to_authenticate_from_ip_filter search *
okta_multiple_users_failing_to_authenticate_from_ip_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
T1110.003 Password Spraying Credential Access
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
APT28
APT29
APT33
Chimera
HEXANE
Lazarus Group
Leafminer
Silent Librarian

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

A source Ip failing to authenticate with multiple users in a short period of time is not common legitimate behavior.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Multiple users failing to authenticate from a single source IP Address - [$src$]. Investigate further to determine if this was authorized. 54 60 90
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