Detection: O365 Compliance Content Search Started

Updated Date: 2024-05-15 ID: f4cabbc7-c19a-4e41-8be5-98daeaccbb50 Author: Mauricio Velazco, Splunk Type: TTP Product: Splunk Enterprise Security

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.

1 `o365_management_activity` Workload=SecurityComplianceCenter Operation=SearchCreated 
2| rename user_id as user 
3| stats count earliest(_time) as firstTime latest(_time) as lastTime by Operation, ObjectId, ExchangeLocations, user, Query  
4|`security_content_ctime(firstTime)` 
5|`security_content_ctime(lastTime)` 
6| `o365_compliance_content_search_started_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
o365_management_activity sourcetype=o365:management:activity
o365_compliance_content_search_started_filter search *
o365_compliance_content_search_started_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1114 Email Collection Collection
T1114.002 Remote Email Collection Collection
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
Magic Hound
Silent Librarian
APT1
APT28
APT29
Chimera
Dragonfly
FIN4
HAFNIUM
Ke3chang
Kimsuky
Leafminer
Magic Hound

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
A new compliance content search was started by $user$ 42 60 70
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset o365 o365:management:activity
Integration ✅ Passing Dataset o365 o365:management:activity

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 2