[metadata]
creation_date = "2024/09/06"
integration = ["windows", "system", "sentinel_one_cloud_funnel", "m365_defender"]
maturity = "production"
min_stack_comments = "Breaking change at 8.13.0 for SentinelOne Integration."
min_stack_version = "8.13.0"
updated_date = "2024/09/16"

[rule]
author = ["Elastic"]
description = """
Identifies the execution of PowerShell with suspicious argument values. This behavior is often observed during malware
installation leveraging PowerShell.
"""
from = "now-9m"
index = [
    "winlogbeat-*",
    "logs-windows.*",
    "logs-system.security*",
    "logs-windows.sysmon_operational-*",
    "logs-sentinel_one_cloud_funnel.*",
    "logs-m365_defender.event-*"
]
language = "eql"
license = "Elastic License v2"
name = "Suspicious Windows Powershell Arguments"
risk_score = 73
rule_id = "83bf249e-4348-47ba-9741-1202a09556ad"
severity = "high"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Execution",
    "Data Source: System",
    "Data Source: Sysmon",
    "Data Source: SentinelOne",
    "Data Source: Microsoft Defender for Endpoint"
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.type == "start" and
 process.name : "powershell.exe" and 
  (
   process.command_line :
        (
          "*^*^*^*^*^*^*^*^*^*",
          "*`*`*`*`*",
          "*+*+*+*+*+*+*",
          "*[char[]](*)*-join*",
          "*Base64String*",
          "*[*Convert]*",
          "*.Compression.*",
          "*-join($*",
          "*.replace*",
          "*MemoryStream*",
          "*WriteAllBytes*",
          "* -enc *",
          "* -ec *",
          "* /e *",
          "* /enc *",
          "* /ec *",
          "*WebClient*",
          "*DownloadFile*",
          "*DownloadString*",
          "* iex*",
          "* iwr*",
          "*Reflection.Assembly*",
          "*Assembly.GetType*",
          "*$env:temp\\*start*",
          "*powercat*",
          "*nslookup -q=txt*",
          "*$host.UI.PromptForCredential*",
          "*Net.Sockets.TCPClient*",
          "*curl *;Start*",
          "powershell.exe \"<#*",
          "*ssh -p *",
          "*http*|iex*",
          "*@SSL\\DavWWWRoot\\*.ps1*",
          "*.lnk*.Seek(0x*",
          "*[string]::join(*",
          "*[Array]::Reverse($*",
          "* hidden $(gc *",
          "*=wscri& set*",
          "*http'+'s://*",
          "*.content|i''Ex*",
          "*//:sptth*",
          "*//:ptth*",
          "*$*=Get-Content*AppData*.SubString(*$*",
          "*=cat *AppData*.substring(*);*$*"
        ) or

      (process.args : "-c" and process.args : "&{'*") or

      (process.args : "-Outfile" and process.args : "Start*") or

      (process.args : "-bxor" and process.args : "0x*") or

      process.args : "$*$*;set-alias" or

      (process.parent.name : ("explorer.exe", "cmd.exe") and 
       process.command_line : ("*-encodedCommand*", "*Invoke-webrequest*", "*WebClient*", "*Reflection.Assembly*"))
  )
'''


[[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/"