[metadata]
creation_date = "2021/08/24"
maturity = "production"
updated_date = "2022/03/31"

[rule]
author = ["Elastic"]
description = "Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access."
false_positives = [
    """
    Security audits, maintenance, and network administrative scripts may trigger this alert when run under web
    processes.
    """,
]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Webshell Detection: Script Process Child of Common Web Processes"
note = """## Triage and analysis

Detections should be investigated to identify if the activity corresponds to legitimate activity. As this rule detects post-exploitation process activity, investigations into this should be prioritized.

## 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://www.microsoft.com/security/blog/2020/02/04/ghost-in-the-shell-investigating-web-shell-attacks/",
]
risk_score = 73
rule_id = "2917d495-59bd-4250-b395-c29409b76086"
severity = "high"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Persistence"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type == "start" and
  process.parent.name : ("w3wp.exe", "httpd.exe", "nginx.exe", "php.exe", "php-cgi.exe", "tomcat.exe") and
  process.name : ("cmd.exe", "cscript.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe", "wmic.exe", "wscript.exe")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1505"
name = "Server Software Component"
reference = "https://attack.mitre.org/techniques/T1505/"
[[rule.threat.technique.subtechnique]]
id = "T1505.003"
name = "Web Shell"
reference = "https://attack.mitre.org/techniques/T1505/003/"



[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1190"
name = "Exploit Public-Facing Application"
reference = "https://attack.mitre.org/techniques/T1190/"


[rule.threat.tactic]
id = "TA0001"
name = "Initial Access"
reference = "https://attack.mitre.org/tactics/TA0001/"