Users Authenticating To Other Azure AD Tenants

Detect when users in your Azure AD tenant are authenticating to other Azure AD Tenants.

Detection logic

selection

resultType: 0
homeTenantId|expand: "%HomeTenantID%"

filter_main_hometenantid

resourceTenantId|contains|expand: "%HomeTenantID%"

Condition

selection and not 1 of filter_main_*

Raw YAML

title: Users Authenticating To Other Azure AD Tenants
id: 5f521e4b-0105-4b72-845b-2198a54487b9
status: test
description: Detect when users in your Azure AD tenant are authenticating to other Azure AD Tenants.
references:
    - https://learn.microsoft.com/en-gb/entra/architecture/security-operations-user-accounts#monitoring-external-user-sign-ins
author: MikeDuddington, '@dudders1'
date: 2022-06-30
modified: 2026-05-08
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.initial-access
    - attack.stealth
    - attack.t1078.004
logsource:
    product: azure
    service: signinlogs
detection:
    selection:
        resultType: 0
        homeTenantId|expand: '%HomeTenantID%'
    filter_main_hometenantid:
        resourceTenantId|contains|expand: '%HomeTenantID%'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: medium