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Suspicious PowerShell Engine ImageLoad

Elastic Stack Serverless Security

Identifies the PowerShell engine being invoked by unexpected processes. Rather than executing PowerShell functionality with powershell.exe, some attackers do this to operate more stealthily.

Rule type: eql

Rule indices:

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

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 5

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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

library where dll.name : ("System.Management.Automation.ni.dll", "System.Management.Automation.dll") and
/* add false positives relevant to your environment here */
not process.executable : ("C:\\Windows\\System32\\RemoteFXvGPUDisablement.exe", "C:\\Windows\\System32\\sdiagnhost.exe") and
not process.executable regex~ """C:\\Program Files( \(x86\))?\\*\.exe""" and
  not process.name :
  (
    "Altaro.SubAgent.exe",
    "AppV_Manage.exe",
    "azureadconnect.exe",
    "CcmExec.exe",
    "configsyncrun.exe",
    "choco.exe",
    "ctxappvservice.exe",
    "DVLS.Console.exe",
    "edgetransport.exe",
    "exsetup.exe",
    "forefrontactivedirectoryconnector.exe",
    "InstallUtil.exe",
    "JenkinsOnDesktop.exe",
    "Microsoft.EnterpriseManagement.ServiceManager.UI.Console.exe",
    "mmc.exe",
    "mscorsvw.exe",
    "msexchangedelivery.exe",
    "msexchangefrontendtransport.exe",
    "msexchangehmworker.exe",
    "msexchangesubmission.exe",
    "msiexec.exe",
    "MsiExec.exe",
    "noderunner.exe",
    "NServiceBus.Host.exe",
    "NServiceBus.Host32.exe",
    "NServiceBus.Hosting.Azure.HostProcess.exe",
    "OuiGui.WPF.exe",
    "powershell.exe",
    "powershell_ise.exe",
    "pwsh.exe",
    "SCCMCliCtrWPF.exe",
    "ScriptEditor.exe",
    "ScriptRunner.exe",
    "sdiagnhost.exe",
    "servermanager.exe",
    "setup100.exe",
    "ServiceHub.VSDetouredHost.exe",
    "SPCAF.Client.exe",
    "SPCAF.SettingsEditor.exe",
    "SQLPS.exe",
    "telemetryservice.exe",
    "UMWorkerProcess.exe",
    "w3wp.exe",
    "wsmprovhost.exe"
  )

Framework: MITRE ATT&CKTM