Parent Process PID Spoofing

Identifies parent process spoofing used to thwart detection. Adversaries may spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: high

Risk score: 73

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://blog.didierstevens.com/2017/03/20/

Tags:

Elastic
Host
Windows
Threat Detection
Defense Evasion

Version: 101

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

/* This rule is compatible with Elastic Endpoint only */

sequence by host.id, user.id with maxspan=3m

 [process where event.type == "start" and
  process.Ext.token.integrity_level_name != "system" and
  (
    process.pe.original_file_name : ("winword.exe", "excel.exe", "outlook.exe", "powerpnt.exe", "eqnedt32.exe",
                                     "fltldr.exe", "mspub.exe", "msaccess.exe", "powershell.exe", "pwsh.exe",
                                     "cscript.exe", "wscript.exe", "rundll32.exe", "regsvr32.exe", "msbuild.exe",
                                     "mshta.exe", "wmic.exe", "cmstp.exe", "msxsl.exe") or

    (process.executable : ("?:\\Users\\*.exe",
                           "?:\\ProgramData\\*.exe",
                           "?:\\Windows\\Temp\\*.exe",
                           "?:\\Windows\\Tasks\\*") and
      (process.code_signature.exists == false or process.code_signature.status : "errorBadDigest")) or

    process.executable : "?:\\Windows\\Microsoft.NET\\*.exe"
  ) and

  not process.executable :
             ("?:\\Windows\\System32\\WerFaultSecure.exe",
              "?:\\WINDOWS\\SysWOW64\\WerFaultSecure.exe",
              "?:\\Windows\\System32\\WerFault.exe",
              "?:\\Windows\\SysWOW64\\WerFault.exe")
  ] by process.pid
 [process where event.type == "start" and
  process.parent.Ext.real.pid > 0 and

  /* process.parent.Ext.real.pid is only populated if the parent process pid doesn't match */
  not (process.name : "msedge.exe" and process.parent.name : "sihost.exe") and

   not process.executable :
             ("?:\\Windows\\System32\\WerFaultSecure.exe",
              "?:\\WINDOWS\\SysWOW64\\WerFaultSecure.exe",
              "?:\\Windows\\System32\\WerFault.exe",
              "?:\\Windows\\SysWOW64\\WerFault.exe")
 ] by process.parent.Ext.real.pid

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
Technique:
- Name: Access Token Manipulation
- ID: T1134
- Reference URL: https://attack.mitre.org/techniques/T1134/
Sub-technique:
- Name: Parent PID Spoofing
- ID: T1134.004
- Reference URL: https://attack.mitre.org/techniques/T1134/004/

« Unusual Network Activity from a Windows System Binary Suspicious .NET Reflection via PowerShell »