Exporting Exchange Mailbox via PowerShell

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Exporting Exchange Mailbox via PowerShell

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Identifies the use of the Exchange PowerShell cmdlet New-MailBoxExportRequest to export the contents of a primary mailbox or archive to a .pst file. Adversaries may target user email to collect sensitive information.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • winlogbeat-*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Collection

Version: 7

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

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process where event.type in ("start", "process_started") and
  process.name: ("powershell.exe", "pwsh.exe", "powershell_ise.exe") and process.args : "New-MailboxExportRequest*"

Framework: MITRE ATT&CKTM