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Description

This analytic detects instances where a user has initiated an eDiscovery search or exported a PST file from the search results in an Office 365 environment. The detection leverages the Office 365 management activity logs, specifically filtering for events categorized under ThreatManagement with the name eDiscovery search started or exported. The initiation of an eDiscovery search or the export of a PST file can be indicative of data exfiltration attempts or unauthorized access to sensitive information. PST files often contain a wealth of sensitive data, including the content of emails. Monitoring for such activities is crucial as they can expose sensitive organizational communications and data. If confirmed as a malicious activity, it suggests that an attacker or insider threat is attempting to gather or exfiltrate data. This can lead to data breaches, loss of intellectual property, or unauthorized access to confidential communications. Immediate investigation is required to determine the scope and intent of the activity and to take appropriate remedial actions.

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

  • Last Updated: 2020-12-16
  • 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
1
2
3
4
5
`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: 2