Unusual Service Host Child Process - Childless Service

Elastic Stack Serverless Security

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 (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[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: 4

Rule authors:

• Elastic

Rule license: Elastic License v2

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.

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")

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Privilege Escalation
  • ID: TA0004
  • Reference URL: https://attack.mitre.org/tactics/TA0004/

• Technique:

  • Name: Process Injection
  • ID: T1055
  • Reference URL: https://attack.mitre.org/techniques/T1055/

• Sub-technique:

  • Name: Process Hollowing
  • ID: T1055.012
  • Reference URL: https://attack.mitre.org/techniques/T1055/012/

• Tactic:

  • Name: Defense Evasion
  • ID: TA0005
  • Reference URL: https://attack.mitre.org/tactics/TA0005/

• Technique:

  • Name: Process Injection
  • ID: T1055
  • Reference URL: https://attack.mitre.org/techniques/T1055/