Suspicious PowerShell Engine ImageLoad

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 (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

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## 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

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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&CK^TM

Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
Sub-technique:
- Name: PowerShell
- ID: T1059.001
- Reference URL: https://attack.mitre.org/techniques/T1059/001/

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