Azure AD User Consent Blocked for Risky Application

name: Azure AD User Consent Blocked for Risky Application
id: 06b8ec9a-d3b5-4882-8f16-04b4d10f5eab
version: 11
creation_date: '2023-11-16'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects instances where Azure AD has blocked a user's attempt to grant consent to a risky or potentially malicious application. This detection leverages Azure AD audit logs, focusing on user consent actions and system-driven blocks. Monitoring these blocked consent attempts is crucial as it highlights potential threats early on, indicating that a user might be targeted or that malicious applications are attempting to infiltrate the organization. If confirmed malicious, this activity suggests that Azure's security measures successfully prevented a harmful application from accessing organizational data, warranting immediate investigation to understand the context and take preventive measures.
data_source:
    - Azure Active Directory Consent to application
search: "`azure_monitor_aad` operationName=\"Consent to application\" properties.result=failure | rename properties.* as * | eval reason_index = if(mvfind('targetResources{}.modifiedProperties{}.displayName', \"ConsentAction.Reason\") >= 0, mvfind('targetResources{}.modifiedProperties{}.displayName', \"ConsentAction.Reason\"), -1) | eval permissions_index = if(mvfind('targetResources{}.modifiedProperties{}.displayName', \"ConsentAction.Permissions\") >= 0, mvfind('targetResources{}.modifiedProperties{}.displayName', \"ConsentAction.Permissions\"), -1) | search reason_index >= 0 | eval reason = mvindex('targetResources{}.modifiedProperties{}.newValue',reason_index) | eval permissions = mvindex('targetResources{}.modifiedProperties{}.newValue',permissions_index) | search reason = \"\\\"Risky application detected\\\"\" | rex field=permissions \"Scope: (?<Scope> [ ^,]+)\" | fillnull | stats count min(_time) as firstTime max(_time) as lastTime by dest user src vendor_account vendor_product reason Scope signature | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `azure_ad_user_consent_blocked_for_risky_application_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 AuditLog log category.
known_false_positives: UPDATE_KNOWN_FALSE_POSITIVES
references:
    - https://attack.mitre.org/techniques/T1528/
    - https://www.microsoft.com/en-us/security/blog/2022/09/22/malicious-oauth-applications-used-to-compromise-email-servers-and-spread-spam/
    - https://learn.microsoft.com/en-us/azure/active-directory/manage-apps/protect-against-consent-phishing
    - https://learn.microsoft.com/en-us/defender-cloud-apps/investigate-risky-oauth
    - https://www.alteredsecurity.com/post/introduction-to-365-stealer
    - https://github.com/AlteredSecurity/365-Stealer
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: Azure AD has blocked $user$ attempt to grant to consent to an application deemed risky.
    entity:
        field: user
        type: user
        score: 50
analytic_story:
    - Azure Active Directory Account Takeover
asset_type: Azure Tenant
mitre_attack_id:
    - T1528
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: identity
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1528/azure_ad_user_consent_blocked/azure_ad_user_consent_blocked.log
          source: Azure AD
          sourcetype: azure:monitor:aad
      test_type: unit