Detection: O365 Multiple Service Principals Created by User

Updated Date: 2024-09-30 ID: a34e65d0-54de-4b02-9db8-5a04522067f6 Author: Mauricio Velazco, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies instances where a single user creates more than three unique OAuth applications within a 10-minute window in the Office 365 environment. It leverages O365 logs from the Unified Audit Log, focusing on the 'Add service principal' operation in Azure Active Directory. This activity is significant as it may indicate a compromised user account or unauthorized actions, potentially leading to broader network infiltration or privilege escalation. If confirmed malicious, this behavior could allow attackers to gain persistent access, escalate privileges, or exfiltrate sensitive information.

Search

 1`o365_management_activity`  Workload=AzureActiveDirectory Operation="Add service principal."  
 2| bucket span=10m _time 
 3| eval len=mvcount('Actor{}.ID') 
 4| eval userType = mvindex('Actor{}.ID',len-1) 
 5| search userType = "User" 
 6| eval displayName = object 
 7| stats count earliest(_time) as firstTime latest(_time) as lastTime values(displayName) as displayName dc(displayName) as unique_apps by src_user 
 8| where unique_apps > 3 
 9| `security_content_ctime(firstTime)` 
10| `security_content_ctime(lastTime)` 
11| `o365_multiple_service_principals_created_by_user_filter`

Data Source

Name	Platform	Sourcetype	Source
O365 Add service principal.	N/A	`'o365:management:activity'`	`'o365'`

Macros Used

Name	Value
o365_management_activity	`sourcetype=o365:management:activity`
o365_multiple_service_principals_created_by_user_filter	`search *`

o365_multiple_service_principals_created_by_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
T1136.003	Cloud Account	Persistence

KillChainPhase.INSTALLATION

NistCategory.DE_AE

Cis18Value.CIS_10

APT29

LAPSUS$

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

You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events.

Known False Positives

Certain users or applications may create multiple service principals in a short period of time for legitimate purposes. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
Multiple OAuth applications were created by $src_user$ in a short period of time	42	70	60

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	`o365`	`o365:management:activity`
Integration	✅ Passing	Dataset	`o365`	`o365:management:activity`

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: 3