New ActiveSyncAllowedDeviceID Added via PowerShelledit

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:

  • winlogbeat-*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

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

Maximum alerts per execution: 100



  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Persistence

Version: 6 (version history)

Added (Elastic Stack release): 7.11.0

Last modified (Elastic Stack release): 7.16.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positivesedit

Legitimate exchange system administration activity.

Rule queryedit

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

Threat mappingedit


Rule version historyedit

Version 6 (7.16.0 release)
  • Updated query, changed from:

    process where event.type in ("start", "process_started") and ("powershell.exe", "pwsh.exe") and process.args : "Set-
Version 4 (7.15.0 release)
  • Formatting only
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only