Detection: Azure AD Service Principal Owner Added

Updated Date: 2024-05-28 ID: 7ddf2084-6cf3-4a44-be83-474f7b73c701 Author: Mauricio Velazco, Gowthamaraj Rajendran, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the addition of a new owner to a Service Principal within an Azure AD tenant. It leverages Azure Active Directory events from the AuditLog log category to identify this activity. This behavior is significant because Service Principals do not support multi-factor authentication or conditional access policies, making them a target for adversaries seeking persistence or privilege escalation. If confirmed malicious, this activity could allow attackers to maintain access to the Azure AD environment with single-factor authentication, potentially leading to unauthorized access and control over critical resources.

 1 `azure_monitor_aad`  operationName="Add owner to application" 
 2| rename properties.* as * 
 3| rename initiatedBy.user.userPrincipalName as initiatedBy 
 4| rename targetResources{}.userPrincipalName as newOwner 
 5| rename targetResources{}.modifiedProperties{}.newValue as displayName 
 6| eval displayName = mvindex(displayName,1) 
 7| where initiatedBy!=newOwner 
 8| stats count min(_time) as firstTime max(_time) as lastTime values(displayName) as displayName by initiatedBy, result, operationName, newOwner 
 9| `security_content_ctime(firstTime)` 
10| `security_content_ctime(lastTime)` 
11| `azure_ad_service_principal_owner_added_filter`

Data Source

Name Platform Sourcetype Source Supported App
Azure Active Directory Add owner to application Azure icon Azure 'azure:monitor:aad' 'Azure AD' N/A

Macros Used

Name Value
azure_monitor_aad sourcetype=azure:monitor:aad
azure_ad_service_principal_owner_added_filter search *
azure_ad_service_principal_owner_added_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
T1098 Account Manipulation Persistence
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT3
APT41
APT5
Dragonfly
FIN13
HAFNIUM
Kimsuky
Lazarus Group
Magic Hound

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 Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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 AuditLog log category.

Known False Positives

Administrator may legitimately add new owners for Service Principals. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A new owner was added for service principal $displayName$ by $initiatedBy$ 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 Azure AD azure:monitor:aad
Integration ✅ Passing Dataset Azure AD azure:monitor:aad

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: 4