Initial Access via OSA Shell Script Piped to Python Interpreter

[rule]
description = """
Detects when an Osascript shell script is piped to a Python interpreter for execution followed by an immediate outbound
network connection for C2 establishment. This activity is observed when an Empire payload is executed for initial
access.
"""
id = "2aade342-d45b-4297-a0e0-4cf0962c9042"
license = "Elastic License v2"
name = "Initial Access via OSA Shell Script Piped to Python Interpreter"
os_list = ["macos"]
version = "1.0.11"

query = '''
sequence by process.parent.entity_id with maxspan=30s
[process where event.type == "start" and event.action == "exec" and 
  process.name == "osascript" and 
  process.args == "-e" and process.command_line like~ "*python*"]
[network where event.type == "start" and event.action == "connection_attempted" and
  process.name like~ "python*" and
   not cidrmatch(destination.ip, 
       "240.0.0.0/4", "233.252.0.0/24", "224.0.0.0/4", "198.19.0.0/16", "192.18.0.0/15", 
       "192.0.0.0/24", "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", 
       "192.0.2.0/24", "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", 
       "100.64.0.0/10", "192.175.48.0/24", "198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24",
       "::1", "FE80::/10", "FF00::/8")]
'''

min_endpoint_version = "8.16.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 1

[[actions]]
action = "kill_process"
field = "process.parent.entity_id"
state = 0

[[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 = "T1059.006"
name = "Python"
reference = "https://attack.mitre.org/techniques/T1059/006/"



[threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"
[[threat]]
framework = "MITRE ATT&CK"

[threat.tactic]
id = "TA0011"
name = "Command and Control"
reference = "https://attack.mitre.org/tactics/TA0011/"

[internal]
min_endpoint_version = "8.16.0"