O365 Email Access By Security Administrator

 Original Source: [splunk source]
Name:O365 Email Access By Security Administrator
id:c6998a30-fef4-4e89-97ac-3bb0123719b4
version:11
date:None
author:Steven Dick
status:production
type:TTP
Description:The following analytic identifies when a user with sufficient access to O365 Security & Compliance portal uses premium investigation features (Threat Explorer) to directly view email. Adversaries may exploit privileged access with this premium feature to enumerate or exfiltrate sensitive data.
Data_source:
  • -Office 365 Universal Audit Log
search:`o365_management_activity` Workload=SecurityComplianceCenter Operation=AdminMailAccess

| rename InternetMessageId as signature_id, UserId as src_user

| fillnull

| stats count min(_time) as firstTime max(_time) as lastTime
BY signature dest user
src vendor_account vendor_product
src_user signature_id

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `o365_email_access_by_security_administrator_filter`


how_to_implement:You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events. Threat Explorer is a premium feature with o365, logging may not be available with proper license.
known_false_positives:Legitamate access by security administators for incident response measures.
References:
  -https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/threat-explorer-investigate-delivered-malicious-email?view=o365-worldwide
drilldown_searches:
 name:'View the detection results for - "$user$" and "$src_user$"'
 search:'%original_detection_search% | search user = "$user$" src_user = "$src_user$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$user$" and "$src_user$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$src_user$") | 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:['Data Exfiltration', 'Azure Active Directory Account Takeover', 'Office 365 Account Takeover']

asset_type:O365 Tenant

mitre_attack_id:['T1114.002', 'T1567']

product:['Splunk Enterprise', 'Splunk Enterprise Security', 'Splunk Cloud']

category:cloud

security_domain:threat

tags:

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566/o365_various_alerts/o365_various_alerts.log
  sourcetype: o365:management:activity
  source: o365
 test_type:'unit'
manual_test:None