Powershell Outbound Network Connection

[rule]
description = """
Detects when Powershell (pwsh) on macOS makes an outbound network connection attempt. Powershell usage on macOS is
extremely rare but usage of Powershell to connect out to the internet is almost always indicative of malicious behavior.
"""
id = "53aa049c-72d1-4ddf-b089-a86059642a35"
license = "Elastic License v2"
name = "Powershell Outbound Network Connection"
os_list = ["macos"]
version = "1.0.12"

query = '''
sequence by process.entity_id with maxspan=30s
[process where event.type == "start" and event.action == "exec" and process.name == "pwsh"]
[network where event.type == "start" and event.action == "connection_attempted" 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 = 1

[[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"