Detection rules › Elastic

PowerShell Empire Script Execution

Source
github.com/elastic/protections-artifacts

Identifies the execution of PowerShell scripts with keywords from known open source Empire penetration testing tool.

MITRE ATT&CK coverage

Rule body

[rule]
description = "Identifies the execution of PowerShell scripts with keywords from known open source Empire penetration testing tool."
id = "a014e5b8-e793-46a4-a006-57c2f908ece1"
license = "Elastic License v2"
name = "PowerShell Empire Script Execution"
os_list = ["windows"]
version = "1.0.2"

query = '''
api where process.Ext.api.name == "AmsiScanBuffer" and
 (process.name in~ ("powershell.exe") or process.Ext.api.parameters.app_name == "PowerShell") and
  process.Ext.api.parameters.buffer :
               ("*%256*%256*-bxor*%256*",
                "*$data ($IV+$K)*|IEX*",
                "*:CurrentListenerName*:ControlServers*",
                "*/admin/get.php,/news.php,/login/process.php*",
                "*/login/process.php*",
                "If($GPF)*")
'''

min_endpoint_version = "8.16.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0
tree = true

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



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

[internal]
min_endpoint_version = "8.16.0"

Stages and Predicates

Stage 1: api

api where process.Ext.api.name == "AmsiScanBuffer" and
 (process.name in~ ("powershell.exe") or process.Ext.api.parameters.app_name == "PowerShell") and
  process.Ext.api.parameters.buffer :
               ("*%256*%256*-bxor*%256*",
                "*$data ($IV+$K)*|IEX*",
                "*:CurrentListenerName*:ControlServers*",
                "*/admin/get.php,/news.php,/login/process.php*",
                "*/login/process.php*",
                "If($GPF)*")

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
process.Ext.api.nameeq
  • AmsiScanBuffer corpus 16 (elastic 16)
field:"process.Ext.api.name" kind:eq value:"AmsiScanBuffer"
process.Ext.api.parameters.app_nameeq
  • PowerShell corpus 10 (elastic 10)
field:"process.Ext.api.parameters.app_name" kind:eq value:"PowerShell"
process.Ext.api.parameters.bufferwildcard
  • *$data ($IV+$K)*|IEX*
  • *%256*%256*-bxor*%256*
  • */admin/get.php,/news.php,/login/process.php*
  • */login/process.php*
  • *:CurrentListenerName*:ControlServers*
  • If($GPF)*
field:"process.Ext.api.parameters.buffer" kind:wildcard
process.namein
  • powershell.exe corpus 184 (elastic 140, splunk 44)
field:"process_name" kind:in value:"powershell.exe"