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Description

The following analytic identifies the assignment of sensitive and privileged Azure Active Directory roles to an Azure AD user. Adversaries and red teams alike may assign these roles to a compromised account to establish Persistence in an Azure AD environment. This detection leverages the O365 Universal Audit Log data source.

  • Type: TTP

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

  • Last Updated: 2024-04-11
  • Author: Steven Dick
  • ID: db435700-4ddc-4c23-892e-49e7525d7d39

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 


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`o365_management_activity` Workload=AzureActiveDirectory Operation IN ("Add member to role.","Add eligible member to role.") 
| eval user = ObjectId, src_user = case(match(mvindex('Actor{}.ID',-1),"User"),mvindex('Actor{}.ID',0),match(mvindex('Actor{}.ID',-1),"ServicePrincipal"),mvindex('Actor{}.ID',3),true(),mvindex('Actor{}.ID',0)), object_name = mvindex('ModifiedProperties{}.NewValue', mvfind('ModifiedProperties{}.Name',"Role\.DisplayName")), object_id = mvindex('ModifiedProperties{}.NewValue', mvfind('ModifiedProperties{}.Name',"Role\.TemplateId")), signature = Operation, result = ResultStatus, category = mvindex('Target{}.ID',2) 
| stats count, min(_time) as firstTime, max(_time) as lastTime by src_user, user, category, result, object_name, object_id, signature 
| lookup privileged_azure_ad_roles azuretemplateid as object_id OUTPUT isprvilegedadrole 
| search isprvilegedadrole="TRUE" category="User" 
| `security_content_ctime(firstTime)`  
| `security_content_ctime(lastTime)` 
| `o365_privileged_role_assigned_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_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:

Required fields

List of fields required to use this analytic.

  • _time
  • Operation
  • ModifiedProperties{}.NewValue
  • ModifiedProperties{}.Name
  • UserId
  • ObjectId
  • Workload

How To Implement

You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events.

Known False Positives

Administrators will legitimately assign the privileged roles users as part of administrative tasks. Microsoft Privileged Identity Management (PIM) may cause false positives / less accurate alerting.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
75.0 75 100 A privileged Azure AD role [$object_name$] was assigned to user $user$ by $src_user$

:information_source: 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

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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