Suspicious WMI Image Load from MS Office

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Identifies a suspicious image load (wmiutils.dll) from Microsoft Office processes. This behavior may indicate adversarial activity where child processes are spawned via Windows Management Instrumentation (WMI). This technique can be used to execute code and evade traditional parent/child processes spawned from Microsoft Office products.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.library-*
  • logs-windows.sysmon_operational-*
  • endgame-*

Severity: low

Risk score: 21

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Execution
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Sysmon

Version: 108

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Setup

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 version 8.2. Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate event.ingested to @timestamp. For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html

Rule query

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any where host.os.type == "windows" and
 (event.category : ("library", "driver") or (event.category == "process" and event.action : "Image loaded*")) and
  process.name : ("WINWORD.EXE", "EXCEL.EXE", "POWERPNT.EXE", "MSPUB.EXE", "MSACCESS.EXE") and
  (?dll.name : "wmiutils.dll" or file.name : "wmiutils.dll")

Framework: MITRE ATT&CKTM