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Description

The following analytic detects instances where a user has initiated an eDiscovery search or exported a PST file in an Office 365 environment. It leverages Office 365 management activity logs, specifically filtering for events under ThreatManagement with the name "eDiscovery search started or exported." This activity is significant as it may indicate data exfiltration attempts or unauthorized access to sensitive information. If confirmed malicious, it suggests an attacker or insider threat is attempting to gather or exfiltrate data, potentially leading to data breaches, loss of intellectual property, or unauthorized access to confidential communications. Immediate investigation is required.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-16
  • Author: Rod Soto, Splunk
  • ID: 5f694cc4-a678-4a60-9410-bffca1b647dc

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1114 Email Collection Collection
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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`o365_management_activity` Category=ThreatManagement Name="eDiscovery search started or exported" 
| stats count earliest(_time) as firstTime latest(_time) as lastTime by Source Severity AlertEntityId Operation Name 
|`security_content_ctime(firstTime)` 
|`security_content_ctime(lastTime)` 
| `o365_pst_export_alert_filter`

Macros

The SPL above uses the following Macros:

:information_source: o365_pst_export_alert_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Category
  • Name
  • Source
  • Severity
  • AlertEntityId
  • Operation

How To Implement

You must install splunk Microsoft Office 365 add-on. This search works with o365:management:activity

Known False Positives

PST export can be done for legitimate purposes but due to the sensitive nature of its content it must be monitored.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
48.0 80 60 User $Source$ has exported a PST file from the search using this operation- $Operation$ with a severity of $Severity$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

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 | version: 3