Unusual Parent Process for cmd.exeedit

Identifies a suspicious parent child process relationship with cmd.exe descending from an unusual process.

Rule type: eql

Rule indices:

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

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

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
process.name : "cmd.exe" and process.parent.name : ("lsass.exe",
"csrss.exe", "epad.exe",
"regsvr32.exe", "dllhost.exe",
"LogonUI.exe", "wermgr.exe",
"spoolsv.exe", "jucheck.exe",
"jusched.exe", "ctfmon.exe",
"taskhostw.exe", "GoogleUpdate.exe",
"sppsvc.exe", "sihost.exe",
"slui.exe", "SIHClient.exe",
"SearchIndexer.exe",
"SearchProtocolHost.exe",
"FlashPlayerUpdateService.exe",
"WerFault.exe", "WUDFHost.exe",
"unsecapp.exe", "wlanext.exe" )

Threat mappingedit

Framework: MITRE ATT&CKTM

Rule version historyedit

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

    event.category:process and event.type:(start or process_started) and
    process.name:cmd.exe and process.parent.name:(lsass.exe or csrss.exe
    or notepad.exe or regsvr32.exe or dllhost.exe or LogonUI.exe or
    wermgr.exe or spoolsv.exe or jucheck.exe or jusched.exe or ctfmon.exe
    or taskhostw.exe or GoogleUpdate.exe or sppsvc.exe or sihost.exe or
    slui.exe or SIHClient.exe or SearchIndexer.exe or
    SearchProtocolHost.exe or FlashPlayerUpdateService.exe or WerFault.exe
    or WUDFHost.exe or unsecapp.exe or wlanext.exe)
Version 3 (7.12.0 release)
  • Formatting only
Version 2 (7.11.2 release)
  • Formatting only