ID | Technique | Tactic |
---|---|---|
T1136.003 | Cloud Account | Persistence |
Detection: Azure AD Service Principal Created
Description
The following analytic detects the creation of a Service Principal in an Azure AD environment. It leverages Azure Active Directory events ingested through EventHub, specifically monitoring the "Add service principal" operation. This activity is significant because Service Principals can be used by adversaries to establish persistence and bypass multi-factor authentication and conditional access policies. If confirmed malicious, this could allow attackers to maintain single-factor access to the Azure AD environment, potentially leading to unauthorized access to resources and prolonged undetected activity.
Search
1`azure_monitor_aad` operationName="Add service principal" properties.initiatedBy.user.id=*
2| rename properties.* as *
3| rename targetResources{}.displayName as displayName
4| rename targetResources{}.type as type
5| stats count min(_time) as firstTime max(_time) as lastTime values(displayName) as displayName by type, user, result, operationName
6| `security_content_ctime(firstTime)`
7| `security_content_ctime(lastTime)`
8| `azure_ad_service_principal_created_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Azure Active Directory Add service principal | Azure | 'azure:monitor:aad' |
'Azure AD' |
Macros Used
Name | Value |
---|---|
azure_monitor_aad | sourcetype=azure:monitor:aad |
azure_ad_service_principal_created_filter | search * |
azure_ad_service_principal_created_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
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 thorough an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLog log category.
Known False Positives
Administrator may legitimately create Service Principal. Filter as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
Service Principal named $displayName$ created by $user$ | 45 | 50 | 90 |
References
-
https://docs.microsoft.com/en-us/azure/active-directory/develop/app-objects-and-service-principals
-
https://www.inversecos.com/2021/10/how-to-backdoor-azure-applications-and.html
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | Azure AD |
azure:monitor:aad |
Integration | ✅ Passing | Dataset | Azure AD |
azure:monitor:aad |
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: 3