Suspicious macOS MS Office Child Process

Identifies suspicious child processes of frequently targeted Microsoft Office applications (Word, PowerPoint, and Excel). These child processes are often launched during exploitation of Office applications or by documents with malicious macros.

Rule type: eql

Rule indices:

logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://blog.malwarebytes.com/cybercrime/2017/02/microsoft-office-macro-malware-targets-macs/

Tags:

Elastic
Host
macOS
Threat Detection
Initial Access

Version: 101

Rule authors:

Elastic

Rule license: Elastic License v2

Rule query

edit

process where event.type in ("start", "process_started") and
 process.parent.name:("Microsoft Word", "Microsoft PowerPoint", "Microsoft Excel") and
 process.name:
 (
   "bash",
   "dash",
   "sh",
   "tcsh",
   "csh",
   "zsh",
   "ksh",
   "fish",
   "python*",
   "perl*",
   "php*",
   "osascript",
   "pwsh",
   "curl",
   "wget",
   "cp",
   "mv",
   "base64",
   "launchctl"
  ) and
  /* noisy false positives related to product version discovery and office errors reporting */
  not process.args:
    (
      "ProductVersion",
      "hw.model",
      "ioreg",
      "ProductName",
      "ProductUserVisibleVersion",
      "ProductBuildVersion",
      "/Library/Application Support/Microsoft/MERP*/Microsoft Error Reporting.app/Contents/MacOS/Microsoft Error Reporting"
    )

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
Technique:
- Name: Phishing
- ID: T1566
- Reference URL: https://attack.mitre.org/techniques/T1566/
Sub-technique:
- Name: Spearphishing Attachment
- ID: T1566.001
- Reference URL: https://attack.mitre.org/techniques/T1566/001/

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