O365 Email Reported By Admin Found Malicious

SPLUNK detection rule by Steven Dick · Apache-2.0

The following analytic detects when an email manually submitted to Microsoft through the Security & Compliance portal is found to be malicious. This capability is an enhanced protection feature that can be used within o365 tenants by administrative users to report potentially malicious emails. This correlation looks for any submission that returns a Phish or Malware verdict upon submission.

name: O365 Email Reported By Admin Found Malicious
id: 94396c3e-7728-422a-9956-e4b77b53dbdf
version: 11
creation_date: '2024-04-07'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: TTP
description: The following analytic detects when an email manually submitted to Microsoft through the Security & Compliance portal is found to be malicious. This capability is an enhanced protection feature that can be used within o365 tenants by administrative users to report potentially malicious emails. This correlation looks for any submission that returns a Phish or Malware verdict upon submission.
data_source:
    - Office 365 Universal Audit Log
search: |-
    `o365_management_activity` Workload=SecurityComplianceCenter Operation=AdminSubmission
      | search RescanVerdict IN (Phish,Malware)
      | rename Id as signature_id, SenderIP as src, Recipients{} as dest_user, P1Sender as src_user
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY dest user src
           vendor_account vendor_product signature
           signature_id dest_user src_user
           Subject SubmissionContent
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `o365_email_reported_by_admin_found_malicious_filter`
how_to_implement: You must install splunk Microsoft Office 365 add-on. This search works with o365:management:activity
known_false_positives: Administrators that submit known phishing training exercises.
references:
    - https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/submissions-outlook-report-messages?view=o365-worldwide
drilldown_searches:
    - name: View the detection results for - "$src_user$" and "$user$"
      search: '%original_detection_search% | search  src_user = "$src_user$" user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src_user$" and "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src_user$", "$user$") | 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: O365 security admin $user$ manually reported a suspicious email from $src_user$
    entity:
        field: src_user
        type: user
        score: 50
threat_objects:
    - field: Subject
      type: email_subject
analytic_story:
    - Spearphishing Attachments
    - Suspicious Emails
asset_type: O365 Tenant
mitre_attack_id:
    - T1566.001
    - T1566.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: threat
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

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

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