[metadata]
creation_date = "2023/02/28"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/04/03"

[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 execution of potentially 
malicious processes through the MOTD utility. 
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "endgame-*"]
language = "eql"
license = "Elastic License v2"
name = "Suspicious Process Spawned from MOTD 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 = 73
rule_id = "4ec47004-b34a-42e6-8003-376a123ea447"
severity = "high"
tags = ["Elastic", "Host", "Linux", "Threat Detection", "Persistence", "Elastic Endgame"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "linux" and 
event.type == "start" and event.action : ("exec", "exec_event") and
process.parent.executable : ("/etc/update-motd.d/*", "/usr/lib/update-notifier/*") and
process.executable : ("*sh", "python*", "perl", "php*")
'''


[[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/"