Potential Process Injection from Malicious Document

ELASTIC detection rule by Elastic · Elastic License v2

Identifies child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, Excel) with unusual process arguments and path. This behavior is often observed during exploitation of Office applications or from documents with malicious macros.

[metadata]
creation_date = "2023/09/25"
integration = ["endpoint"]
maturity = "production"
updated_date = "2024/05/21"

[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
Identifies child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, Excel) with unusual
process arguments and path. This behavior is often observed during exploitation of Office applications or from documents
with malicious macros.
"""
from = "now-119m"
index = ["logs-endpoint.events.process-*"]
interval = "60m"
language = "eql"
license = "Elastic License v2"
name = "Potential Process Injection from Malicious Document"
risk_score = 21
rule_id = "1c5a04ae-d034-41bf-b0d8-96439b5cc774"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Windows",
    "Use Case: Threat Detection",
    "Tactic: Defense Evasion",
    "Tactic: Privilege Escalation",
    "Tactic: Initial Access",
    "Rule Type: BBR",
    "Data Source: Elastic Defend",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
process where host.os.type == "windows" and event.action == "start" and
  process.parent.name : ("excel.exe", "powerpnt.exe", "winword.exe") and
  process.args_count == 1 and
  process.executable : (
    "?:\\Windows\\SysWOW64\\*.exe", "?:\\Windows\\system32\\*.exe"
  ) and
  not (process.executable : "?:\\Windows\\System32\\spool\\drivers\\x64\\*" and
       process.code_signature.trusted == true and not process.code_signature.subject_name : "Microsoft *") and
  not process.executable : (
    "?:\\Windows\\Sys*\\Taskmgr.exe",
    "?:\\Windows\\Sys*\\ctfmon.exe",
    "?:\\Windows\\System32\\notepad.exe")
'''


[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1055"
name = "Process Injection"
reference = "https://attack.mitre.org/techniques/T1055/"


[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 = "T1055"
name = "Process Injection"
reference = "https://attack.mitre.org/techniques/T1055/"


[rule.threat.tactic]
id = "TA0004"
name = "Privilege Escalation"
reference = "https://attack.mitre.org/tactics/TA0004/"
[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1566"
name = "Phishing"
reference = "https://attack.mitre.org/techniques/T1566/"
[[rule.threat.technique.subtechnique]]
id = "T1566.001"
name = "Spearphishing Attachment"
reference = "https://attack.mitre.org/techniques/T1566/001/"



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

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

bacf659d-c5f0-4e97-a531-0fb067b5d45b

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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