Unsigned or Untrusted Binary Execution via XPC call

[rule]
description = """
Detects the execution of an unsigned or untrusted binary by a shell interpreter via an XPC call. This activity can be
carried out in several ways but the most common is when a Login Item gets created that is specified to execute a
specific binary (in this instance an unsigned or untrusted binary). Threat actors will often utilize Login Items as a
persistence mechanism to launch their payloads on system boot.
"""
id = "ecd7fb9b-4a70-4a8f-8035-2df7fc90cfd5"
license = "Elastic License v2"
name = "Unsigned or Untrusted Binary Execution via XPC call"
os_list = ["macos"]
version = "1.0.6"

query = '''
process where event.type == "start" and event.action == "exec" and
 process.Ext.effective_parent.name == "xpcproxy" and
 process.parent.name in ("sh", "zsh", "bash") and
 (process.code_signature.trusted == false or process.code_signature.exists == false) and 
 process.args_count <= 2 and 
 process.executable like~ ("/Volumes/*", "/Applications/*", "/Users/Shared/*", "/Library/Application Support/*", "/Users/*/Library/*", "/tmp/*", "/private/tmp/*", "/var/tmp/*") and
 not process.name like~ "python*"
'''

min_endpoint_version = "8.7.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.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 = "T1059.004"
name = "Unix Shell"
reference = "https://attack.mitre.org/techniques/T1059/004/"


[[threat.technique]]
id = "T1559"
name = "Inter-Process Communication"
reference = "https://attack.mitre.org/techniques/T1559/"
[[threat.technique.subtechnique]]
id = "T1559.003"
name = "XPC Services"
reference = "https://attack.mitre.org/techniques/T1559/003/"



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

[internal]
min_endpoint_version = "8.7.0"