Azure AD User Consent Denied for OAuth Application

Name:Azure AD User Consent Denied for OAuth Application
id:bb093c30-d860-4858-a56e-cd0895d5b49c
version:14
date:None
author:Mauricio Velazco, Splunk
status:production
type:TTP
Description:The following analytic identifies instances where a user has denied consent to an OAuth application seeking permissions within the Azure AD environment. This detection leverages Azure AD's audit logs, specifically focusing on user consent actions with error code 65004. Monitoring denied consent actions is significant as it can indicate users recognizing potentially suspicious or untrusted applications. If confirmed malicious, this activity could suggest attempts by unauthorized applications to gain access, potentially leading to data breaches or unauthorized actions within the environment. Understanding these denials helps refine security policies and enhance user awareness.
Data_source:

• -Azure Active Directory Sign-in activity

search:`azure_monitor_aad` operationName="Sign-in activity" properties.status.errorCode=65004

| rename properties.* as *

| fillnull

| stats count min(_time) as firstTime max(_time) as lastTime
BY dest user src
vendor_account vendor_product appDisplayName
status.failureReason signature

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `azure_ad_user_consent_denied_for_oauth_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 SignInLogs log category.
known_false_positives:Users may deny consent for legitimate applications by mistake, filter as needed.
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'
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

tags:

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_declined/azure_ad_user_consent_declined.log
  source: Azure AD
  sourcetype: azure:monitor:aad
 test_type:'unit'
manual_test:None