New ActiveSyncAllowedDeviceID Added via PowerShell

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New ActiveSyncAllowedDeviceID Added via PowerShell

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Identifies the use of the Exchange PowerShell cmdlet, Set-CASMailbox, to add a new ActiveSync allowed device. 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
  • Persistence

Version: 5

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where event.type in ("start", "process_started") and
  process.name: ("powershell.exe", "pwsh.exe") and process.args : "Set-CASMailbox*ActiveSyncAllowedDeviceIDs*"

Framework: MITRE ATT&CKTM