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detections/cloud/azure_ad_multi_factor_authentication_disabled.yml

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+name: Azure AD Multi-Factor Authentication Disabled
+id: 482dd42a-acfa-486b-a0bb-d6fcda27318e
+version: 1
+date: '2022-08-10'
+author: Mauricio Velazco, Splunk
+type: TTP
+datamodel: []
+description: The following analytic identifies an attempt to disable multi-factor authentication for an Azure AD user. An adversary who has obtained access to an Azure AD tenant 
+  may disable multi-factor authentication as a way to plant a backdoor and maintain persistence using a valid account.
+  This way the attackers can keep persistance in the environment without adding new users.
+search: '`azuread` "body.operationName"="Disable Strong Authentication" 
+  | rename body.properties.* as *
+  | rename targetResources{}.userPrincipalName as userPrincipalName
+  | rename targetResources{}.type as type
+  | rename initiatedBy.user.userPrincipalName as initiatedBy
+  | stats values(userPrincipalName) by _time, type, body.operationName, initiatedBy, result
+  | `azure_ad_multi_factor_authentication_disabled_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. 
+  Specifically, this analytic leverages the AuditLogs log category.
+known_false_positives: Legitimate use case may require for users to disable MFA. Filter as needed.
+references:
+- https://docs.microsoft.com/en-us/azure/active-directory/authentication/concept-mfa-howitworks
+- https://docs.microsoft.com/en-us/azure/active-directory/authentication/howto-mfa-userstates
+- https://attack.mitre.org/tactics/TA0005/
+- https://attack.mitre.org/techniques/T1556/
+tags:
+  analytic_story:
+  - Azure Active Directory Account Takeover
+  asset_type: Azure Active Directory
+  cis20:
+  - CIS 3
+  - CIS 5
+  - CIS 16
+  confidence: 90
+  context:
+  - Source:Cloud Data
+  - Stage:Persistence
+  - Stage:Defense Evasion
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1556/azuread/azure-audit.log
+  impact: 50
+  kill_chain_phases:
+  - Installation
+  - Actions on Objectives
+  message: MFA disabled for User $userPrincipalName$ initiated by $initiatedBy$  
+  mitre_attack_id:
+  - T1556
+  nist:
+  - DE.CM
+  observable:
+  - name: userPrincipalName
+    type: User
+    role:
+    - Victim
+  - name: initiatedBy
+    type: User
+    role:
+    - Attacker
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - body.properties.targetResources{}.userPrincipalName
+  - body.properties.targetResources{}.type
+  - body.properties.initiatedBy.user.userPrincipalName
+  - body.properties.result
+  risk_score: 45
+  security_domain: identity

tests/cloud/azure_ad_multi_factor_authentication_disabled.test.yml

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+name: Azure AD Multi-Factor Authentication Disabled Unit Test
+tests:
+- name: Azure AD Multi-Factor Authentication Disabled
+  file: cloud/azure_ad_multi_factor_authentication_disabled.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: -24h
+  latest_time: now
+  attack_data:
+  - file_name: azure-audit.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1556/azuread/azure-audit.log
+    source: mscs:azure:eventhub
+    sourcetype: mscs:azure:eventhub
+    update_timestamp: true