[metadata]
creation_date = "2023/02/28"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup, New Term"
min_stack_version = "8.6.0"
updated_date = "2023/04/05"

[rule]
author = ["Elastic"]
description = """
Message of the day (MOTD) is the message that is presented to the user when a user connects to a Linux server via SSH or
a serial connection. Linux systems contain several default MOTD files located in the "/etc/update-motd.d/" and
"/usr/lib/update-notifier/" directories. These scripts run as the root user every time a user connects over SSH or a
serial connection. Adversaries may create malicious MOTD files that grant them persistence onto the target every time a
user connects to the system by executing a backdoor script or command. This rule detects the creation of potentially
malicious files within the default MOTD file directories.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "endgame-*"]
language = "kuery"
license = "Elastic License v2"
name = "Potential Persistence Through MOTD File Creation Detected"
references = [
    "https://pberba.github.io/security/2022/02/06/linux-threat-hunting-for-persistence-initialization-scripts-and-shell-configuration/#10-boot-or-logon-initialization-scripts-motd"
]
risk_score = 47
rule_id = "96d11d31-9a79-480f-8401-da28b194608f"
severity = "medium"
tags = ["Elastic", "Host", "Linux", "Threat Detection", "Persistence", "Elastic Endgame"]
type = "new_terms"

query = '''
host.os.type :"linux" and event.action:("creation" or "file_create_event" or "rename" or "file_rename_event") and 
file.path : (/etc/update-motd.d/* or /usr/lib/update-notifier/*) and not 
process.executable : ("/usr/bin/dpkg" or "/usr/bin/dockerd" or "/bin/rpm") and not 
file.extension : "swp"
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1037"
name = "Boot or Logon Initialization Scripts"
reference = "https://attack.mitre.org/techniques/T1037/"



[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"


[rule.new_terms]
field = "new_terms_fields"
value = ["file.path", "process.name"]
[[rule.new_terms.history_window_start]]
field = "history_window_start"
value = "now-7d"