[metadata]
creation_date = "2020/09/02"
maturity = "production"
updated_date = "2020/12/09"

[rule]
author = ["Elastic"]
description = """
Identifies child processes of unusual instances of RunDLL32 where the command line parameters were suspicious. Misuse of
RunDLL32 could indicate malicious activity.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "winlogbeat-*"]
language = "eql"
license = "Elastic License"
name = "Unusual Child Processes of RunDLL32"
risk_score = 21
rule_id = "f036953a-4615-4707-a1ca-dc53bf69dcd5"
severity = "high"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Defense Evasion"]
type = "eql"

query = '''
sequence with maxspan=1h
  [process where event.type in ("start", "process_started") and
     (process.name : "rundll32.exe" or process.pe.original_file_name == "RUNDLL32.EXE") and
      process.args_count == 1
  ] by process.entity_id
  [process where event.type in ("start", "process_started") and process.parent.name : "rundll32.exe"
  ] by process.parent.entity_id
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1218"
name = "Signed Binary Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1218/"
[[rule.threat.technique.subtechnique]]
id = "T1218.011"
name = "Rundll32"
reference = "https://attack.mitre.org/techniques/T1218/011/"


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

