Detection rules › Splunk

Azure AD New MFA Method Registered For User

Status
production
Severity
medium
Group by
action, aws::recipientAccountId, aws::userAgent, dest, result, resultDescription, signature, src, user, vendor_product
Author
Mauricio Velazco, Splunk
Source
github.com/splunk/security_content

The following analytic detects the registration of a new Multi-Factor Authentication (MFA) method for an Azure AD account. It leverages Azure AD AuditLogs to identify when a user registers new security information. This activity is significant because adversaries who gain unauthorized access to an account may add their own MFA method to maintain persistence. If confirmed malicious, this could allow attackers to bypass existing security controls, maintain long-term access, and potentially escalate their privileges within the environment.

Known false positives

  • Newly onboarded users who are registering an MFA method for the first time will also trigger this detection.

MITRE ATT&CK coverage

Telemetry coverage

PlatformRecord / event type
AzureUser registered security info

Rules detecting the same action

These rules filter on the same operation.

Rule body

name: Azure AD New MFA Method Registered For User
id: 2628b087-4189-403f-9044-87403f777a1b
version: 14
creation_date: '2023-01-30'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects the registration of a new Multi-Factor Authentication (MFA) method for an Azure AD account. It leverages Azure AD AuditLogs to identify when a user registers new security information. This activity is significant because adversaries who gain unauthorized access to an account may add their own MFA method to maintain persistence. If confirmed malicious, this could allow attackers to bypass existing security controls, maintain long-term access, and potentially escalate their privileges within the environment.
data_source:
    - Azure Active Directory User registered security info
search: |-
    `azure_monitor_aad` category=AuditLogs operationName="User registered security info" properties.operationType=Add
      | rename properties.* as *
      | rename targetResources{}.* as *
      | rename userAgent as user_agent
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY action dest user
           src vendor_account vendor_product
           user_agent result resultDescription
           signature
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `azure_ad_new_mfa_method_registered_for_user_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 through an EventHub. This analytic was written to be used with the azure:monitor:aad sourcetype leveraging the AuditLogs log category.
known_false_positives: Newly onboarded users who are registering an MFA method for the first time will also trigger this detection.
references:
    - https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-mfa-howitworks
    - https://attack.mitre.org/techniques/T1556/
    - https://attack.mitre.org/techniques/T1556/006/
    - https://twitter.com/jhencinski/status/1618660062352007174
finding:
    title: A new MFA method was registered for user $user$
    entity:
        field: user
        type: user
        score: 50
threat_objects:
    - field: src
      type: ip_address
analytic_story:
    - Compromised User Account
    - Azure Active Directory Account Takeover
    - Scattered Lapsus$ Hunters
asset_type: Azure Active Directory
mitre_attack_id:
    - T1556.006
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: identity

Stages and Predicates

Stage 1: search

`azure_monitor_aad` category=AuditLogs operationName="User registered security info" properties.operationType=Add

Stage 2: rename

| rename properties.* as *

Stage 3: rename

| rename targetResources{}.* as *

Stage 4: rename

| rename userAgent as user_agent

Stage 5: fillnull

| fillnull

Stage 6: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    BY action dest user
       src vendor_account vendor_product
       user_agent result resultDescription
       signature

Stage 7: search

| `security_content_ctime(firstTime)`

Stage 8: search

| `security_content_ctime(lastTime)`

Stage 9: search

| `azure_ad_new_mfa_method_registered_for_user_filter`

Indicators

These rows show field, operator, and value matches.