Unusual Service Host Child Process - Childless Service

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: 101

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

edit

Rule query

edit

process where 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_i4x50\\lib\\lexexe.exe") and
          process.parent.args : "imgsvc")

Framework: MITRE ATT&CK^TM

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/

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