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.process-*
  • logs-windows.sysmon_operational-*
  • endgame-*
  • logs-sentinel_one_cloud_funnel.*

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:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Execution
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Sysmon
  • Data Source: SentinelOne

Version: 211

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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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 version 8.2. Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate event.ingested to @timestamp. For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html

Rule query

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process where host.os.type == "windows" and event.type == "start" 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" ) and
  not (process.parent.name : "dllhost.exe" and process.parent.args : "/Processid:{CA8C87C1-929D-45BA-94DB-EF8E6CB346AD}")

Framework: MITRE ATT&CKTM