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Description

The following analytic identifies instances where a service principal in Azure Active Directory assigns app roles without standard admin consent. It uses Entra ID logs from the azure_monitor_aad data source, focusing on the "Add app role assignment to service principal" operation. This detection is significant as it highlights potential bypasses of critical administrative consent processes, which could lead to unauthorized privileges being granted. If confirmed malicious, this activity could allow attackers to exploit automation to assign sensitive permissions without proper oversight, potentially compromising the security of the Azure AD environment.

  • Type: TTP

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

  • Last Updated: 2024-07-02
  • Author: Mauricio Velazco, Splunk
  • ID: 9d4fea43-9182-4c5a-ada8-13701fd5615d

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1098.003 Additional Cloud Roles Persistence, Privilege Escalation
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`azure_monitor_aad` (operationName="Add app role assignment to service principal" OR operationName="Add member to role*") src_user_type=servicePrincipal  
| rename properties.* as *   
| eval roleId = mvindex('targetResources{}.modifiedProperties{}.newValue', 0)  
| eval roleValue = mvindex('targetResources{}.modifiedProperties{}.newValue', 1)  
| eval roleDescription = mvindex('targetResources{}.modifiedProperties{}.newValue', 2)  
| eval user_id = mvindex('targetResources{}.id', 0), user=coalesce(user,mvindex('targetResources{}.displayName', 0)) 
| rename initiatedBy.app.displayName as src_user  
| stats count earliest(_time) as firstTime latest(_time) as lastTime by src_user user user_id roleId roleValue roleDescription 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)`  
| `azure_ad_admin_consent_bypassed_by_service_principal_filter`

Macros

The SPL above uses the following Macros:

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

Required fields

List of fields required to use this analytic.

  • _time
  • operationName
  • targetResources{}.modifiedProperties{}.newValue
  • targetResources{}.id

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

Service Principals are sometimes configured to legitimately bypass the consent process for purposes of automation. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
54.0 90 60 Service principal $src_user$ bypassed the admin consent process and granted permissions to $user$

: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

source | version: 3