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Description

This detection identifies when a single service principal in Azure AD creates more than three unique OAuth applications within a 10-minute span, potentially signaling malicious activity. It monitors the 'Add service principal' operation, focusing on the activity of service principals rather than individual users. By aggregating the creation events over a 10-minute period, the analytic tracks how many distinct OAuth applications are created by each service principal. This is key for SOC teams to pinpoint potential attack staging, where an attacker might use a compromised or malicious service principal to rapidly establish multiple service principals, facilitating network infiltration or expansion. While the default threshold is set to trigger on more than three applications, security teams should adjust this to fit their specific environment's norm

  • Type: Anomaly

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

  • Last Updated: 2024-02-07
  • Author: Mauricio Velazco, Splunk
  • ID: 66cb378f-234d-4fe1-bb4c-e7878ff6b017

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1136.003 Cloud Account Persistence
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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 `azure_monitor_aad` operationName="Add service principal" properties.initiatedBy.app.appId=* 
| rename properties.* as * 
| bucket span=10m _time 
| rename targetResources{}.displayName as displayName 
| rename targetResources{}.type as type 
| rename initiatedBy.app.displayName as src_user 
| stats min(_time) as firstTime max(_time) as lastTime values(displayName) as displayName dc(displayName) as unique_apps by src_user 
| where unique_apps > 3 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `azure_ad_multiple_service_principals_created_by_sp_filter`

Macros

The SPL above uses the following Macros:

:information_source: azure_ad_multiple_service_principals_created_by_sp_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

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 through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLogs log category.

Known False Positives

Certain users or applications may create multiple service principals in a short period of time for legitimate purposes. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
42.0 70 60 Multiple OAuth applications were created by $src_user$ in a short period of time

: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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