Unusual Parent Process for cmd.exe

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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: 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: 8

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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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 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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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" )

Framework: MITRE ATT&CKTM