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Description

This detection focuses on identifying instances where a single user creates more than three unique OAuth applications within a 10-minute timeframe in Azure AD, a potential indicator of malicious activity. By monitoring the 'Add service principal' operation and aggregating the data with a 10-minute bucket span, it tracks the number of distinct OAuth applications created by each user. This analytic is crucial for SOC teams to detect possible staging of attacks, where an adversary might rapidly create multiple service principals as part of their infiltration or expansion strategy within the network. The threshold of three applications is set to flag unusual behavior, but security teams are advised to adjust this value to suit the normal operational patterns of their environment

  • Type: Anomaly

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

  • Last Updated: 2024-02-07
  • Author: Mauricio Velazco, Splunk
  • ID: 32880707-f512-414e-bd7f-204c0c85b758

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.user.id=* 
| rename properties.* as * 
| bucket span=10m _time 
| rename targetResources{}.displayName as displayName 
| 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_user_filter`

Macros

The SPL above uses the following Macros:

:information_source: azure_ad_multiple_service_principals_created_by_user_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
  • properties.initiatedBy.user.id
  • targetResources{}.displayName
  • src_user

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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