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Description

This detection aims to identify instances where a single service principal creates more than three unique OAuth applications within a 10-minute timeframe, using O365 logs from the Unified Audit Log. The focus is on tracking the 'Add service principal' operation within the Office 365 Azure Active Directory environment. The query effectively buckets events in 10-minute intervals, specifically scrutinizing the actions of service principals. By quantifying the number of distinct OAuth applications each service principal establishes, the analytic provides critical insights for SOC teams into potentially anomalous or malicious activities. These activities could include a compromised or malicious service principal being used to create multiple service principals, which might be indicative of an attempt to expand control or access within the network. Security teams are advised to adapt the threshold of three applications to align with their typical operational baseline

  • Type: Anomaly

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

  • Last Updated: 2024-02-07
  • Author: Mauricio Velazco, Splunk
  • ID: ef4c3f20-d1ad-4ad1-a3f4-d5f391c005fe

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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`o365_management_activity` Workload=AzureActiveDirectory Operation="Add service principal."  
| bucket span=10m _time 
| eval len=mvcount('Actor{}.ID') 
| eval userType = mvindex('Actor{}.ID',len-1) 
| search userType = "ServicePrincipal" 
| eval displayName = object 
| stats count earliest(_time) as firstTime latest(_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)` 
| `o365_multiple_service_principals_created_by_sp_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_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
  • Workload
  • Operation
  • Actor{}.ID
  • src_user
  • object

How To Implement

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

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

source | version: 1