Detection: O365 New Federated Domain Added

Updated Date: 2025-02-10 ID: e155876a-6048-11eb-ae93-0242ac130002 Author: Rod Soto, Mauricio Velazco Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies the addition of a new federated domain in an Office 365 environment. This behavior is detected by analyzing Office 365 management activity logs, specifically filtering for Workload=Exchange and Operation="Add-FederatedDomain". The addition of a new federated domain is significant as it may indicate unauthorized changes or potential compromises. If confirmed malicious, attackers could establish a backdoor, bypass security measures, or exfiltrate data, leading to data breaches and unauthorized access to sensitive information. Immediate investigation is required to review the details of the added domain and any concurrent suspicious activities.

1`o365_management_activity` Operation IN ("*add*", "*new*") AND Operation="*domain*" 
2| eval src="NA" 
3| fillnull 
4| stats count values(ModifiedProperties{}.NewValue) as new_value by user user_agent authentication_service signature Workload src vendor_account vendor_product dest 
5| `security_content_ctime(firstTime)` 
6| `security_content_ctime(lastTime)` 
7| `o365_new_federated_domain_added_filter`

Data Source

Name Platform Sourcetype Source
O365 N/A 'o365:management:activity' 'o365'

Macros Used

Name Value
o365_management_activity sourcetype=o365:management:activity
o365_new_federated_domain_added_filter search *
o365_new_federated_domain_added_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
Installation
DE.CM
CIS 10

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
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

You must install splunk Microsoft Office 365 add-on. This search works with o365:management:activity.

Known False Positives

The creation of a new Federated domain is not necessarily malicious, however these events need to be followed closely, as it may indicate federated credential abuse or backdoor via federated identities at a similar or different cloud provider.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

User $user$ has added a new federated domain $new_value$

Risk Object Risk Object Type Risk Score Threat Objects
user user 64 No Threat Objects

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: 8