Detection rules › Splunk

O365 Compliance Content Search Started

Status
production
Severity
medium
Group by
ExchangeLocations, Query, aws::recipientAccountId, dest, signature, src, user, vendor_product
Author
Mauricio Velazco, Splunk
Source
github.com/splunk/security_content

The following analytic detects when a content search is initiated within the Office 365 Security and Compliance Center. It leverages the SearchCreated operation from the o365_management_activity logs under the SecurityComplianceCenter workload. This activity is significant as it may indicate an attempt to access sensitive organizational data, including emails and documents. If confirmed malicious, this could lead to unauthorized data access, potential data exfiltration, and compliance violations. Monitoring this behavior helps ensure the integrity and security of organizational data.

MITRE ATT&CK coverage

Rule body splunk

name: O365 Compliance Content Search Started
id: f4cabbc7-c19a-4e41-8be5-98daeaccbb50
version: 12
creation_date: '2024-04-17'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects when a content search is initiated within the Office 365 Security and Compliance Center. It leverages the SearchCreated operation from the o365_management_activity logs under the SecurityComplianceCenter workload. This activity is significant as it may indicate an attempt to access sensitive organizational data, including emails and documents. If confirmed malicious, this could lead to unauthorized data access, potential data exfiltration, and compliance violations. Monitoring this behavior helps ensure the integrity and security of organizational data.
data_source: []
search: |-
    `o365_management_activity` Workload=SecurityComplianceCenter Operation=SearchCreated
      | rename user_id as user
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY signature dest user
           src vendor_account vendor_product
           ExchangeLocations Query
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `o365_compliance_content_search_started_filter`
how_to_implement: You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events.
known_false_positives: Compliance content searches may be executed for legitimate purposes, filter as needed.
references:
    - https://attack.mitre.org/techniques/T1114/002/
    - https://learn.microsoft.com/en-us/purview/ediscovery-content-search-overview
    - https://learn.microsoft.com/en-us/purview/ediscovery-keyword-queries-and-search-conditions
    - https://learn.microsoft.com/en-us/purview/ediscovery-search-for-activities-in-the-audit-log
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: A new compliance content search was started by $user$
    entity:
        field: user
        type: user
        score: 50
analytic_story:
    - Office 365 Collection Techniques
asset_type: O365 Tenant
mitre_attack_id:
    - T1114.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: cloud
security_domain: audit
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1114.002/o365_compliance_content_search_started/o365_compliance_content_search_started.log
          sourcetype: o365:management:activity
          source: o365
      test_type: unit

Stages and Predicates

Stage 1: search

`o365_management_activity` Workload=SecurityComplianceCenter Operation=SearchCreated

Stage 2: rename

| rename user_id as user

Stage 3: fillnull

| fillnull

Stage 4: stats

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

Stage 5: search

| `security_content_ctime(firstTime)`

Stage 6: search

| `security_content_ctime(lastTime)`

Stage 7: search

| `o365_compliance_content_search_started_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Operationeq
  • SearchCreated
Workloadeq
  • SecurityComplianceCenter
sourcetypeeq
  • o365:management:activity