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Elastic Docs ›Elastic Security Solution [8.11] ›Downloadable rule update v8.11.11

Unusual Service Host Child Process - Childless Service

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Unusual Service Host Child Process - Childless Service

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Identifies unusual child processes of Service Host (svchost.exe) that traditionally do not spawn any child processes. This may indicate a code injection or an equivalent form of exploitation.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • winlogbeat-*
  • logs-windows.sysmon_operational-*
  • endgame-*

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: Defense Evasion
  • Tactic: Privilege Escalation
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Sysmon

Version: 109

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.parent.name : "svchost.exe" and

  /* based on svchost service arguments -s svcname where the service is known to be childless */
  process.parent.args : (
    "WdiSystemHost", "LicenseManager", "StorSvc", "CDPSvc", "cdbhsvc", "BthAvctpSvc", "SstpSvc", "WdiServiceHost",
    "imgsvc", "TrkWks", "WpnService", "IKEEXT", "PolicyAgent", "CryptSvc", "netprofm", "ProfSvc", "StateRepository",
    "camsvc", "LanmanWorkstation", "NlaSvc", "EventLog", "hidserv", "DisplayEnhancementService", "ShellHWDetection",
    "AppHostSvc", "fhsvc", "CscService", "PushToInstall"
  ) and

  /* unknown FPs can be added here */
  not process.name : ("WerFault.exe", "WerFaultSecure.exe", "wermgr.exe") and
  not (process.executable : "?:\\Windows\\System32\\RelPost.exe" and process.parent.args : "WdiSystemHost") and
  not (
    process.name : "rundll32.exe" and
    process.args : "?:\\WINDOWS\\System32\\winethc.dll,ForceProxyDetectionOnNextRun" and
    process.parent.args : "WdiServiceHost"
  ) and
  not (
    process.executable : (
      "?:\\Program Files\\*",
      "?:\\Program Files (x86)\\*",
      "?:\\Windows\\System32\\Kodak\\kds_?????\\lib\\lexexe.exe"
    ) and process.parent.args : "imgsvc"
  )

Framework: MITRE ATT&CKTM

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