PST Export Alert Using New-ComplianceSearchAction — Sigma Rule

Rule metadata and linked tags

Author: Nikita Khalimonenkov. Source status: test; severity: medium. Source dates: 2022-11-17 / not supplied.

{
  "service": "threat_management",
  "product": "m365"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: bde3905507db16348395c697ceb808ea8d7b5f2790390505836456227e6a7cb2

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: PST Export Alert Using New-ComplianceSearchAction
id: 6897cd82-6664-11ed-9022-0242ac120002
related:
    - id: 18b88d08-d73e-4f21-bc25-4b9892a4fdd0
      type: similar
status: test
description: Alert when a user has performed an export to a search using 'New-ComplianceSearchAction' with the '-Export' flag. This detection will detect PST export even if the 'eDiscovery search or exported' alert is disabled in the O365.This rule will apply to ExchangePowerShell usage and from the cloud.
references:
    - https://learn.microsoft.com/en-us/powershell/module/exchange/new-compliancesearchaction?view=exchange-ps
author: Nikita Khalimonenkov
date: 2022-11-17
tags:
    - attack.collection
    - attack.t1114
logsource:
    service: threat_management
    product: m365
detection:
    selection:
        eventSource: SecurityComplianceCenter
        Payload|contains|all:
            - 'New-ComplianceSearchAction'
            - 'Export'
            - 'pst'
    condition: selection
falsepositives:
    - Exporting a PST can be done for legitimate purposes by legitimate sources, but due to the sensitive nature of PST content, it must be monitored.
level: medium

Original YAML and metadata in JSON

False positives

• Exporting a PST can be done for legitimate purposes by legitimate sources, but due to the sensitive nature of PST content, it must be monitored.

Source references

• https://learn.microsoft.com/en-us/powershell/module/exchange/new-compliancesearchaction?view=exchange-ps