Suspicious Explorer Child Processedit

Identifies a suspicious Windows explorer child process. Explorer.exe can be abused to launch malicious scripts or executables from a trusted parent process.

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
  • Initial Access

Version: 5 (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

Investigation guideedit

## 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 queryedit

process where event.type in ("start", "process_started") and ( : ("cscript.exe", "wscript.exe", "powershell.exe",
"rundll32.exe", "cmd.exe", "mshta.exe", "regsvr32.exe") or in ("cscript.exe", "wscript.exe",
"PowerShell.EXE", "RUNDLL32.EXE", "Cmd.Exe", "MSHTA.EXE",
"REGSVR32.EXE") ) and /* Explorer started via DCOM */ : "explorer.exe" and process.parent.args :
"-Embedding" and not process.parent.args: ( /*
Noisy CLSID_SeparateSingleProcessExplorerHost Explorer COM Class IDs
*/ "/factory,{5BD95610-9434-43C2-886C-57852CC8A120}",
"/factory,{ceff45ee-c862-41de-aee2-a022c81eda92}" )

Threat mappingedit


Rule version historyedit

Version 5 (8.2.0 release)
  • Formatting only
Version 4 (7.13.0 release)
  • Updated query, changed from:

    process where event.type in ("start", "process_started") and : ("cscript.exe", "wscript.exe", "powershell.exe",
    "rundll32.exe", "cmd.exe", "mshta.exe", "regsvr32.exe") and /*
    Explorer started via DCOM */ : "explorer.exe"
    and process.parent.args : "-Embedding"
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only