Windows Office Startup Folder File Drop for Persistence via Office Documents

Alerts when Office documents/templates are created in Word/Excel startup folders on Windows, suggesting persistence attempts.

FreeReviewedSigma · High · v2
Product
windows
Category
file_event
Author
Max Altgelt (Nextron Systems), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-06-02
Updated
2026-07-31
title: Windows Office Startup Folder File Drop for Persistence via Office Documents
id: c8555838-3658-48e9-bca3-9091d03a0ce8
status: test
description: This rule identifies creation of Microsoft Office documents in default Word or Excel startup folder paths that can be used to trigger persistent execution when Office loads templates or documents. Attackers may leverage these locations to establish persistence using Office file types, relying on Windows file event telemetry and matching target filename path and extension patterns. It excludes activity where the initiating image is WINWORD.exe or EXCEL.exe to reduce noise from legitimate Office operations.
references:
  - https://insight-jp.nttsecurity.com/post/102hojk/operation-restylink-apt-campaign-targeting-japanese-companies
  - https://learn.microsoft.com/en-us/office/troubleshoot/excel/use-startup-folders
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_office_startup_persistence.yml
author: Max Altgelt (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-06-02
modified: 2023-06-22
tags:
  - attack.persistence
  - attack.t1137
logsource:
  category: file_event
  product: windows
detection:
  selection_word_paths:
    - TargetFilename|contains: \Microsoft\Word\STARTUP
    - TargetFilename|contains|all:
        - \Office
        - \Program Files
        - \STARTUP
  selection_word_extension:
    TargetFilename|endswith:
      - .doc
      - .docm
      - .docx
      - .dot
      - .dotm
      - .rtf
  selection_excel_paths:
    - TargetFilename|contains: \Microsoft\Excel\XLSTART
    - TargetFilename|contains|all:
        - \Office
        - \Program Files
        - \XLSTART
  selection_excel_extension:
    TargetFilename|endswith:
      - .xls
      - .xlsm
      - .xlsx
      - .xlt
      - .xltm
  filter_main_office:
    Image|endswith:
      - \WINWORD.exe
      - \EXCEL.exe
  condition: (all of selection_word_* or all of selection_excel_*) and not filter_main_office
falsepositives:
  - Loading a user environment from a backup or a domain controller
  - Synchronization of templates
level: high
license: DRL-1.1
related:
  - id: 0e20c89d-2264-44ae-8238-aeeaba609ece
    type: derived