Detection: O365 Compliance Content Search Started

Updated Date: 2024-09-30 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.

Search

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

No data sources specified for this detection.

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

Ember Bear

Magic Hound

Scattered Spider

Silent Librarian

APT1

APT28

APT29

Chimera

Dragonfly

FIN4

HAFNIUM

Ke3chang

Kimsuky

Leafminer

Magic Hound

Star Blizzard

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

Office 365 Collection Techniques

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: 4