[metadata]
creation_date = "2020/01/07"
maturity = "production"
updated_date = "2022/07/06"

[rule]
author = ["Elastic"]
description = "Identifies the execution of a shell process with suspicious arguments which may be indicative of reverse shell activity."
from = "now-9m"
index = ["auditbeat-*", "logs-endpoint.events.*"]
language = "eql"
license = "Elastic License v2"
name = "Potential Reverse Shell Activity via Terminal"
note = """## Setup

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.
"""
references = [
    "https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md",
    "https://github.com/WangYihang/Reverse-Shell-Manager",
    "https://www.netsparker.com/blog/web-security/understanding-reverse-shells/",
]
risk_score = 73
rule_id = "a1a0375f-22c2-48c0-81a4-7c2d11cc6856"
severity = "high"
tags = ["Elastic", "Host", "Linux", "macOS", "Threat Detection", "Execution"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type in ("start", "process_started") and
  process.name in ("sh", "bash", "zsh", "dash", "zmodload") and
  process.args : ("*/dev/tcp/*", "*/dev/udp/*", "*zsh/net/tcp*", "*zsh/net/udp*") and

  /* noisy FPs */
  not (process.parent.name : "timeout" and process.executable : "/var/lib/docker/overlay*") and
  not process.command_line : ("*/dev/tcp/sirh_db/*", "*/dev/tcp/remoteiot.com/*", "*dev/tcp/elk.stag.one/*", "*dev/tcp/kafka/*", "*/dev/tcp/$0/$1*", "*/dev/tcp/127.*", "*/dev/udp/127.*", "*/dev/tcp/localhost/*") and
  not process.parent.command_line : "runc init"
'''


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


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