Detection: Azure AD Privileged Role Assigned to Service Principal

Updated Date: 2024-05-31 ID: 5dfaa3d3-e2e4-4053-8252-16d9ee528c41 Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the assignment of privileged roles to service principals in Azure Active Directory (AD). It leverages the AuditLogs log category from ingested Azure AD events. This activity is significant because assigning elevated permissions to non-human entities can lead to unauthorized access or malicious activities. If confirmed malicious, attackers could exploit these service principals to gain elevated access to Azure resources, potentially compromising sensitive data and critical infrastructure. Monitoring this behavior helps prevent privilege escalation and ensures the security of Azure environments.

 1 `azure_monitor_aad`  operationName="Add member to role" 
 2| rename properties.* as * 
 3| search "targetResources{}.type"=ServicePrincipal 
 4| rename initiatedBy.user.userPrincipalName as initiatedBy 
 5| rename targetResources{}.modifiedProperties{}.newValue  as roles 
 6| eval role=mvindex(roles,1) 
 7| rename targetResources{}.displayName as apps 
 8| eval displayName=mvindex(apps,0) 
 9| stats count min(_time) as firstTime max(_time) as lastTime values(displayName) as displayName by initiatedBy, result, operationName, role 
10| lookup privileged_azure_ad_roles azureadrole AS role OUTPUT isprvilegedadrole description 
11| search isprvilegedadrole = True 
12| `security_content_ctime(firstTime)` 
13| `security_content_ctime(lastTime)` 
14| `azure_ad_privileged_role_assigned_to_service_principal_filter`

Data Source

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

Macros Used

Name Value
azure_monitor_aad sourcetype=azure:monitor:aad
azure_ad_privileged_role_assigned_to_service_principal_filter search *
azure_ad_privileged_role_assigned_to_service_principal_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
T1098.003 Additional Cloud Roles Privilege Escalation
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT3
APT41
APT5
Dragonfly
FIN13
HAFNIUM
Kimsuky
Lazarus Group
Magic Hound
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 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. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLog log category.

Known False Positives

Administrators may legitimately assign the privileged roles to Service Principals as part of administrative tasks. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A privileged Azure AD role was assigned to the Service Principal $displayName$ initiated by $initiatedBy$ 35 70 50
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: 3