sigma-rules/rules/windows/execution_via_compiled_html_file.toml

[metadata]
creation_date = "2020/02/18"
maturity = "production"
updated_date = "2022/07/20"

[rule]
author = ["Elastic"]
description = """
Compiled HTML files (.chm) are commonly distributed as part of the Microsoft HTML Help system. Adversaries may conceal
malicious code in a CHM file and deliver it to a victim for execution. CHM content is loaded by the HTML Help executable
program (hh.exe).
"""
false_positives = [
    """
    The HTML Help executable program (hh.exe) runs whenever a user clicks a compiled help (.chm) file or menu item that
    opens the help file inside the Help Viewer. This is not always malicious, but adversaries may abuse this technology
    to conceal malicious code.
    """,
]
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.*", "logs-windows.*"]
language = "eql"
license = "Elastic License v2"
name = "Process Activity via Compiled HTML File"
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.
"""
risk_score = 47
rule_id = "e3343ab9-4245-4715-b344-e11c56b0a47f"
severity = "medium"
tags = ["Elastic", "Host", "Windows", "Threat Detection", "Execution"]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where event.type in ("start", "process_started") and
 process.parent.name : "hh.exe" and
 process.name : ("mshta.exe", "cmd.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe", "cscript.exe", "wscript.exe")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1204"
name = "User Execution"
reference = "https://attack.mitre.org/techniques/T1204/"
[[rule.threat.technique.subtechnique]]
id = "T1204.002"
name = "Malicious File"
reference = "https://attack.mitre.org/techniques/T1204/002/"



[rule.threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1218"
name = "System Binary Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1218/"
[[rule.threat.technique.subtechnique]]
id = "T1218.001"
name = "Compiled HTML File"
reference = "https://attack.mitre.org/techniques/T1218/001/"



[rule.threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"