Detection: Azure AD Privileged Role Assigned

Updated Date: 2024-05-29 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.

Search

 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| stats count min(_time) as firstTime max(_time) as lastTime values(user) as user by initiatedBy, result, operationName, role 
 7| lookup privileged_azure_ad_roles azureadrole AS role OUTPUT isprvilegedadrole description 
 8| search isprvilegedadrole = True 
 9| `security_content_ctime(firstTime)` 
10| `security_content_ctime(lastTime)` 
11| `azure_ad_privileged_role_assigned_filter`

Data Source

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

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	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 will legitimately assign the privileged roles users 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 for User $user$ initiated by $initiatedBy$	63	70	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: 3