sigma-rules/rules/windows/execution_command_shell_via_rundll32.toml

[metadata]
creation_date = "2020/10/19"
maturity = "production"
updated_date = "2022/03/31"

[rule]
author = ["Elastic"]
description = "Identifies command shell activity started via RunDLL32, which is commonly abused by attackers to host malicious code."
false_positives = ["Microsoft Windows installers leveraging RunDLL32 for installation."]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Command Shell Activity Started via RunDLL32"
note = """## Setup

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.
"""
risk_score = 21
rule_id = "9ccf3ce0-0057-440a-91f5-870c6ad39093"
severity = "low"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type == "start" and
 process.name : ("cmd.exe", "powershell.exe") and
  process.parent.name : "rundll32.exe" and process.parent.command_line != null and
  /* common FPs can be added here */
  not process.parent.args : ("C:\\Windows\\System32\\SHELL32.dll,RunAsNewUser_RunDLL",
                             "C:\\WINDOWS\\*.tmp,zzzzInvokeManagedCustomActionOutOfProc")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"
[[rule.threat.technique.subtechnique]]
id = "T1059.001"
name = "PowerShell"
reference = "https://attack.mitre.org/techniques/T1059/001/"



[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"