Unusual Service Host Child Process - Childless Serviceedit

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.*

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
  • Defense Evasion
  • Privilege Escalation

Version: 6

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guideedit


Rule queryedit

process where event.type in ("start", "process_started") 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_i4x50\\lib\\lexexe.exe") and
          process.parent.args : "imgsvc")

Framework: MITRE ATT&CKTM