Perl Script File Creation or Modification

[rule]
description = """
Detects when a .pl file gets created or modified by a non-perl binary. Perl is a scripting language that comes
pre-installed on macOS and is a trusted binary offering an extensive set of capabilities and advantages to an adversary.
Its use on a macOS system is not common and therefore specific behaviors exhibited can be classified as malicious or
suspicious at least.
"""
id = "f2fa4350-6700-46d1-b79c-fedd385f6984"
license = "Elastic License v2"
name = "Perl Script File Creation or Modification"
os_list = ["macos"]
version = "1.0.8"

query = '''
sequence by process.entity_id with maxspan=15s
[network where event.type == "start"]
[file where event.action == "modification" and file.extension == "pl" and 
  (process.code_signature.trusted == false or process.code_signature.exists == false) and
  file.path like ("/Users/Shared/*", "/tmp/*", "/private/tmp/*", "/var/tmp/*", "/private/var/tmp/*") and
  not Effective_process.executable like "/nix/store/*-nix-*/bin/nix"]
'''

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

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



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

[internal]
min_endpoint_version = "8.16.0"