IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
« Network Traffic to Rare Destination Country New or Modified Federation Domain »
Elastic Docs ›Elastic Security Solution [8.2] ›Detections and alerts ›Prebuilt rule reference

New ActiveSyncAllowedDeviceID Added via PowerShell

edit

New ActiveSyncAllowedDeviceID Added via PowerShell

edit

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: 5 minutes

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: 7 (version history)

Added (Elastic Stack release): 7.11.0

Last modified (Elastic Stack release): 8.2.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

edit

Legitimate exchange system administration activity.

Investigation guide

edit
## 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

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

Threat mapping

edit

Framework: MITRE ATT&CKTM

Rule version history

edit
Version 7 (8.2.0 release)
  • Formatting only
Version 6 (7.16.0 release)

  • Updated query, changed from:

    process where event.type in ("start", "process_started") and
process.name: ("powershell.exe", "pwsh.exe") and process.args : "Set-
CASMailbox*ActiveSyncAllowedDeviceIDs*"
Version 4 (7.15.0 release)
  • Formatting only
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only
« Network Traffic to Rare Destination Country New or Modified Federation Domain »