Detection: Azure AD Multiple Service Principals Created by SP

Description

The following analytic detects when a single service principal in Azure AD creates more than three unique OAuth applications within a 10-minute span. It leverages Azure AD audit logs, specifically monitoring the 'Add service principal' operation initiated by service principals. This behavior is significant as it may indicate an attacker using a compromised or malicious service principal to rapidly establish multiple service principals, potentially staging an attack. If confirmed malicious, this activity could facilitate network infiltration or expansion, allowing the attacker to gain unauthorized access and persist within the environment.

Search

 1 `azure_monitor_aad` operationName="Add service principal" properties.initiatedBy.app.appId=* 
 2| rename properties.* as * 
 3| bucket span=10m _time 
 4| rename targetResources{}.displayName as displayName 
 5| rename targetResources{}.type as type 
 6| rename initiatedBy.app.displayName as src_user 
 7| stats min(_time) as firstTime max(_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| `azure_ad_multiple_service_principals_created_by_sp_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Azure Active Directory Add service principal	Azure	'azure:monitor:aad'	'Azure AD'	N/A

Macros Used

Annotations

Default Configuration

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

Implementation

You must install the latest version of Splunk Add-on for Microsoft Cloud Services from Splunkbase(https://splunkbase.splunk.com/app/3110/#/details). You must be ingesting Azure Active Directory events into your Splunk environment through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLogs log category.

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

• Azure Active Directory Persistence

• NOBELIUM Group

Risk Based Analytics (RBA)

References

• https://attack.mitre.org/techniques/T1136/003/

• https://www.microsoft.com/en-us/security/blog/2024/01/25/midnight-blizzard-guidance-for-responders-on-nation-state-attack/

Detection Testing

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