Detection: O365 Multiple Service Principals Created by User

Updated Date: 2024-05-21 ID: a34e65d0-54de-4b02-9db8-5a04522067f6 Author: Mauricio Velazco, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies instances where a single user creates more than three unique OAuth applications within a 10-minute window in the Office 365 environment. It leverages O365 logs from the Unified Audit Log, focusing on the 'Add service principal' operation in Azure Active Directory. This activity is significant as it may indicate a compromised user account or unauthorized actions, potentially leading to broader network infiltration or privilege escalation. If confirmed malicious, this behavior could allow attackers to gain persistent access, escalate privileges, or exfiltrate sensitive information.

 1`o365_management_activity`  Workload=AzureActiveDirectory Operation="Add service principal."  
 2| bucket span=10m _time 
 3| eval len=mvcount('Actor{}.ID') 
 4| eval userType = mvindex('Actor{}.ID',len-1) 
 5| search userType = "User" 
 6| eval displayName = object 
 7| stats count earliest(_time) as firstTime latest(_time) as lastTime values(displayName) as displayName dc(displayName) as unique_apps by src_user 
 8| where unique_apps > 3 
 9| `security_content_ctime(firstTime)` 
10| `security_content_ctime(lastTime)` 
11| `o365_multiple_service_principals_created_by_user_filter`

Data Source

Name Platform Sourcetype Source Supported App
O365 Add service principal. N/A 'o365:management:activity' 'o365' N/A

Macros Used

Name Value
o365_management_activity sourcetype=o365:management:activity
o365_multiple_service_principals_created_by_user_filter search *
o365_multiple_service_principals_created_by_user_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1136.003 Cloud Account Persistence
KillChainPhase.INSTALLATION
NistCategory.DE_AE
Cis18Value.CIS_10
APT29
LAPSUS$

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Multiple OAuth applications were created by $src_user$ in a short period of time 42 70 60
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset o365 o365:management:activity
Integration ✅ Passing Dataset o365 o365:management:activity

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: GitHub | Version: 2