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Description

This detection focuses on identifying instances in Azure Active Directory where a service principal assigns app roles without standard admin consent, using Entra ID logs. It operates on the azure_monitor_aad data source, scrutinizing the "Add app role assignment to service principal" operation, specifically from service principals. The query dissects details such as role ID, value, and description, important for understanding the nature of the roles being assigned. Monitoring this in a SOC is critical as it flags potential bypasses of vital administrative consent processes in Azure AD, which could result in unauthorized privileges being granted. A true positive detection suggests that a service principal may be exploiting automation to assign sensitive permissions without proper oversight.

  • Type: TTP

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

  • Last Updated: 2024-02-09
  • 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" 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 dest_user = mvindex('targetResources{}.id', 0) 
| rename initiatedBy.app.displayName as src_user 
| stats count earliest(_time) as firstTime latest(_time) as lastTime by src_user dest_user 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 $dest_user$

: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: 1