defense_evasion_parent_process_pid_spoofing.toml

[metadata]
creation_date = "2021/07/14"
maturity = "production"
updated_date = "2021/07/14"

[rule]
author = ["Elastic"]
description = """
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.
"""
from = "now-9m"
index = ["logs-endpoint.events.*"]
language = "eql"
license = "Elastic License v2"
name = "Parent Process PID Spoofing"
references = ["https://blog.didierstevens.com/2017/03/20/"]
risk_score = 73
rule_id = "c88d4bd0-5649-4c52-87ea-9be59dbfbcf2"
severity = "high"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
type = "eql"

query = '''
/* This rule is compatible with Elastic Endpoint only */

sequence by host.id, user.id with maxspan=5m
 [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\\Microsoft.NET\\*.exe",
                          "?:\\Windows\\Temp\\*.exe",
                          "?:\\Windows\\Tasks\\*") or
    process.code_signature.trusted != true
  )
  ] 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")
 ] by process.parent.Ext.real.pid
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
name = "Access Token Manipulation"
id = "T1134"
reference = "https://attack.mitre.org/techniques/T1134/"
[[rule.threat.technique.subtechnique]]
name = "Parent PID Spoofing"
id = "T1134.004"
reference = "https://attack.mitre.org/techniques/T1134/004/"



[rule.threat.tactic]
name = "Defense Evasion"
id = "TA0005"
reference = "https://attack.mitre.org/tactics/TA0005/"