Azure AD New Federated Domain Added

SPLUNK detection rule by Mauricio Velazco, Gowthamaraj Rajendran, Splunk · Apache-2.0

The following analytic detects the addition of a new federated domain within an Azure Active Directory tenant. It leverages Azure AD AuditLogs to identify successful "Set domain authentication" operations. This activity is significant as it may indicate the use of the Azure AD identity federation backdoor technique, allowing an adversary to establish persistence. If confirmed malicious, the attacker could impersonate any user, bypassing password and MFA requirements, potentially leading to unauthorized access and control over the Azure AD environment.

name: Azure AD New Federated Domain Added
id: a87cd633-076d-4ab2-9047-977751a3c1a0
version: 15
creation_date: '2022-09-02'
modification_date: '2026-05-13'
author: Mauricio Velazco, Gowthamaraj Rajendran, Splunk
status: production
type: TTP
description: The following analytic detects the addition of a new federated domain within an Azure Active Directory tenant. It leverages Azure AD AuditLogs to identify successful "Set domain authentication" operations. This activity is significant as it may indicate the use of the Azure AD identity federation backdoor technique, allowing an adversary to establish persistence. If confirmed malicious, the attacker could impersonate any user, bypassing password and MFA requirements, potentially leading to unauthorized access and control over the Azure AD environment.
data_source:
    - Azure Active Directory Set domain authentication
search: |-
    `azure_monitor_aad` operationName="Set domain authentication" "properties.result"=success
      | rename properties.* as *
      | rename targetResources{}.displayName as domain
      | rename userAgent as user_agent
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY dest user src
           vendor_account vendor_product user_agent
           domain signature
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `azure_ad_new_federated_domain_added_filter`
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. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLogs log category.
known_false_positives: In most organizations, domain federation settings will be updated infrequently. Filter as needed.
references:
    - https://www.mandiant.com/resources/remediation-and-hardening-strategies-microsoft-365-defend-against-apt29-v13
    - https://o365blog.com/post/federation-vulnerability/
    - https://www.inversecos.com/2021/11/how-to-detect-azure-active-directory.html
    - https://www.mandiant.com/resources/blog/detecting-microsoft-365-azure-active-directory-backdoors
    - https://attack.mitre.org/techniques/T1484/002/
drilldown_searches:
    - name: View the detection results for - "$user$"
      search: '%original_detection_search% | search  user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: A new federated domain, $domain$ , was added by $user$
    entity:
        field: user
        type: user
        score: 50
analytic_story:
    - Azure Active Directory Persistence
    - Scattered Lapsus$ Hunters
    - Hellcat Ransomware
    - Storm-0501 Ransomware
asset_type: Azure Active Directory
mitre_attack_id:
    - T1484.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: threat
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.002/new_federated_domain/azure-audit.log
          source: Azure AD
          sourcetype: azure:monitor:aad
      test_type: unit

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cb03d330-3055-484e-8496-67d90a4785cf

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