[metadata]
creation_date = "2020/03/25"
integration = ["endpoint", "windows"]
maturity = "production"
min_stack_comments = "Multiple field support in the New Terms rule type was added in Elastic 8.6"
min_stack_version = "8.6.0"
updated_date = "2023/10/23"

[rule]
author = ["Elastic"]
description = """
An instance of MSBuild, the Microsoft Build Engine, was started by a script or the Windows command interpreter. This
behavior is unusual and is sometimes used by malicious payloads.
"""
false_positives = ["The Build Engine is commonly used by Windows developers but use by non-engineers is unusual."]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "kuery"
license = "Elastic License v2"
name = "Microsoft Build Engine Started by a Script Process"
risk_score = 21
rule_id = "9d110cb3-5f4b-4c9a-b9f5-53f0a1707ae2"
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 version 8.2.
Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
`event.ingested` to @timestamp.
For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
"""
severity = "low"
tags = ["Domain: Endpoint",
        "OS: Windows",
        "Use Case: Threat Detection",
        "Tactic: Defense Evasion",
        "Tactic: Execution",
        "Data Source: Elastic Defend"
        ]
timestamp_override = "event.ingested"
type = "new_terms"

query = '''
host.os.type:windows and event.category:process and event.type:start and (
  process.name.caseless:"msbuild.exe" or process.pe.original_file_name:"MSBuild.exe") and 
  process.parent.name:("cmd.exe" or "powershell.exe" or "pwsh.exe" or "powershell_ise.exe" or "cscript.exe" or
    "wscript.exe" or "mshta.exe")
'''

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

[[rule.threat.technique]]
id = "T1127"
name = "Trusted Developer Utilities Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1127/"

[[rule.threat.technique.subtechnique]]
id = "T1127.001"
name = "MSBuild"
reference = "https://attack.mitre.org/techniques/T1127/001/"

[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"
[[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.technique.subtechnique]]
id = "T1059.001"
name = "PowerShell"
reference = "https://attack.mitre.org/techniques/T1059/001/"
[[rule.threat.technique.subtechnique]]
id = "T1059.003"
name = "Windows Command Shell"
reference = "https://attack.mitre.org/techniques/T1059/003/"
[[rule.threat.technique.subtechnique]]
id = "T1059.005"
name = "Visual Basic"
reference = "https://attack.mitre.org/techniques/T1059/005/"



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

[rule.new_terms]
field = "new_terms_fields"
value = ["host.id", "user.name", "process.command_line"]

[[rule.new_terms.history_window_start]]
field = "history_window_start"
value = "now-14d"