Azure AD Privileged Role Assigned

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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.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2024-05-29
• Author: Mauricio Velazco, Gowthamaraj Rajendran, Splunk
• ID: a28f0bc3-3400-4a6e-a2da-89b9e95f0d2a

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1098	Account Manipulation	Persistence, Privilege Escalation

T1098.003

Additional Cloud Roles

Persistence, Privilege Escalation

Kill Chain Phase

• Installation
• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

 `azure_monitor_aad`  "operationName"="Add member to role" 
| rename properties.*  as * 
| rename initiatedBy.user.userPrincipalName as initiatedBy 
| rename targetResources{}.modifiedProperties{}.newValue  as roles 
| eval role=mvindex(roles,1) 
| stats count min(_time) as firstTime max(_time) as lastTime values(user) as user by initiatedBy, result, operationName, role 
| lookup privileged_azure_ad_roles azureadrole AS role OUTPUT isprvilegedadrole description 
| search isprvilegedadrole = True 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `azure_ad_privileged_role_assigned_filter`

Macros

The SPL above uses the following Macros:

• azure_monitor_aad
• security_content_ctime

azure_ad_privileged_role_assigned_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Lookups

The SPL above uses the following Lookups:

• privileged_azure_ad_roles with data

Required fields

List of fields required to use this analytic.

• _time
• user
• properties.targetResources{}.type
• properties.initiatedBy.user.userPrincipalName
• properties.result

How To Implement

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

• Azure Active Directory Persistence
• NOBELIUM Group

RBA

Risk Score	Impact	Confidence	Message
63.0	70	90	A privileged Azure AD role was assigned for User $user$ initiated by $initiatedBy$

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://docs.microsoft.com/en-us/azure/active-directory/roles/concept-understand-roles
• https://docs.microsoft.com/en-us/azure/active-directory/roles/permissions-reference
• https://adsecurity.org/?p=4277
• https://www.mandiant.com/resources/detecting-microsoft-365-azure-active-directory-backdoors
• https://docs.microsoft.com/en-us/azure/active-directory/roles/security-planning
• https://attack.mitre.org/techniques/T1098/003/

Test Dataset

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

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