[metadata]
creation_date = "2023/09/20"
integration = ["endpoint"]
maturity = "production"
min_stack_comments = "New fields added: required_fields, related_integrations, setup"
min_stack_version = "8.3.0"
updated_date = "2023/09/20"

[rule]
author = ["Elastic"]
description = """
Monitors for the execution of background processes with process arguments capable of opening a socket in the /dev/tcp 
channel. This may indicate the creation of a backdoor reverse connection, and should be investigated further. 
"""
from = "now-9m"
index = ["logs-endpoint.events.*"]
language = "eql"
license = "Elastic License v2"
name = "Potential Reverse Shell via Background Process"
risk_score = 47
rule_id = "259be2d8-3b1a-4c2c-a0eb-0c8e77f35e39"
severity = "medium"
timestamp_override = "event.ingested"
tags = ["Domain: Endpoint",
        "OS: Linux",
        "Use Case: Threat Detection",
        "Tactic: Execution",
        "Data Source: Elastic Defend"
        ]
type = "eql"
query = '''
process where host.os.type == "linux" and event.action == "exec" and event.type == "start" and 
process.name in ("setsid", "nohup") and process.args : "*/dev/tcp/*0>&1*" and 
process.parent.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish")
'''

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

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

[[rule.threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"

[[rule.threat.technique.subtechnique]]
id = "T1059.004"
name = "Unix Shell"
reference = "https://attack.mitre.org/techniques/T1059/004/"

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

[rule.threat.tactic]
name = "Command and Control"
id = "TA0011"
reference = "https://attack.mitre.org/tactics/TA0011/"

[[rule.threat.technique]]
name = "Application Layer Protocol"
id = "T1071"
reference = "https://attack.mitre.org/techniques/T1071/"