sigma-rules/rules/linux/persistence_linux_backdoor_user_creation.toml

[metadata]
creation_date = "2023/03/07"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/06/22"

[rule]
author = ["Elastic"]
description = """
Identifies the attempt to create a new backdoor user by setting the user's UID to 0. Attackers may alter a user's UID to 
0 to establish persistence on a system.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "endgame-*"]
language = "eql"
license = "Elastic License v2"
name = "Potential Linux Backdoor User Account Creation"
risk_score = 47
rule_id = "494ebba4-ecb7-4be4-8c6f-654c686549ad"
severity = "medium"
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 in ("exec", "exec_event") and process.name == "usermod" and
process.args : "-u" and process.args : "0" and process.args : "-o"
'''

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1136"
name = "Create Account"
reference = "https://attack.mitre.org/techniques/T1136/"

[[rule.threat.technique.subtechnique]]
id = "T1136.001"
name = "Local Account"
reference = "https://attack.mitre.org/techniques/T1136/001/"

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