Detection: Azure AD Privileged Role Assigned

Updated Date: 2025-02-10 ID: a28f0bc3-3400-4a6e-a2da-89b9e95f0d2a Author: Mauricio Velazco, Gowthamaraj Rajendran, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the assignment of privileged Azure Active Directory roles to a user. It leverages Azure AD audit logs, specifically monitoring the "Add member to role" operation. This activity is significant as adversaries may assign privileged roles to compromised accounts to maintain persistence within the Azure AD environment. If confirmed malicious, this could allow attackers to escalate privileges, access sensitive information, and maintain long-term control over the Azure AD infrastructure.

 1`azure_monitor_aad` "operationName"="Add member to role" 
 2| rename properties.* as * 
 3| rename initiatedBy.user.userPrincipalName as initiatedBy 
 4| rename targetResources{}.modifiedProperties{}.newValue as roles 
 5| eval role=mvindex(roles,1) 
 6| fillnull 
 7| stats count min(_time) as firstTime max(_time) as lastTime by dest user src vendor_account vendor_product initiatedBy result role signature 
 8| lookup privileged_azure_ad_roles azureadrole AS role OUTPUT isprvilegedadrole description 
 9| search isprvilegedadrole = True 
10| `security_content_ctime(firstTime)` 
11| `security_content_ctime(lastTime)` 
12| `azure_ad_privileged_role_assigned_filter`

Data Source

Name Platform Sourcetype Source
Azure Active Directory Add member to role Azure icon Azure 'azure:monitor:aad' 'Azure AD'

Macros Used

Name Value
azure_monitor_aad sourcetype=azure:monitor:aad
azure_ad_privileged_role_assigned_filter search *
azure_ad_privileged_role_assigned_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
T1098.003 Additional Cloud Roles Persistence
Exploitation
Installation
DE.CM
CIS 10

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 will legitimately assign the privileged roles users as part of administrative tasks. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

A privileged Azure AD role was assigned for User $user$ initiated by $initiatedBy$

Risk Object Risk Object Type Risk Score Threat Objects
initiatedBy user 63 No Threat Objects
user user 63 No Threat Objects

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: 9