Windows Office Applications Creating Executable/Script Files with Suspicious Extensions

Flags Office application processes creating .exe/.dll/.ps1 and other script or executable files on Windows.

FreeReviewedSigma · High · v2

Product: windows
Category: file_event
Author: Vadim Khrykov (ThreatIntel), Cyb3rEng (Rule), Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2021-08-23
Updated: 2026-07-31

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1204.002Malicious File
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags file creation events where a Microsoft Office process (Excel, Access, Publisher, PowerPoint, Visio, or Word) creates files ending in executable or script extensions. Attackers may use Office applications to drop and execute payloads or staging components using these commonly abused file types. The detection relies on Windows file event telemetry containing the creating process image path and the created target filename, with exclusions for specific known cache/temp locations to reduce noise.

Reporting behind it

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Windows Office Applications Creating Executable/Script Files with Suspicious Extensions

Pivot detection · T1204.002 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-file-creation-by-microsoft-office-with-executable-or-script-extensions-c7a74c80

title: Windows Office Applications Creating Executable/Script Files with Suspicious Extensions
id: 93307671-1387-4342-ad6f-d0e18fbc72d8
status: test
description: This rule flags file creation events where a Microsoft Office process (Excel, Access, Publisher, PowerPoint, Visio, or Word) creates files ending in executable or script extensions. Attackers may use Office applications to drop and execute payloads or staging components using these commonly abused file types. The detection relies on Windows file event telemetry containing the creating process image path and the created target filename, with exclusions for specific known cache/temp locations to reduce noise.
references:
  - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
  - https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/Threat%20Intelligence/The%20DFIR%20Report/20210329_Sodinokibi_(aka_REvil)_Ransomware.yaml
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_office_susp_file_extension.yml
author: Vadim Khrykov (ThreatIntel), Cyb3rEng (Rule), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2021-08-23
modified: 2025-10-17
tags:
  - attack.t1204.002
  - attack.execution
logsource:
  product: windows
  category: file_event
detection:
  selection1:
    Image|endswith:
      - \excel.exe
      - \msaccess.exe
      - \mspub.exe
      - \powerpnt.exe
      - \visio.exe
      - \winword.exe
  selection2:
    TargetFilename|endswith:
      - .bat
      - .cmd
      - .com
      - .dll
      - .exe
      - .hta
      - .ocx
      - .proj
      - .ps1
      - .scf
      - .scr
      - .sys
      - .vbe
      - .vbs
      - .wsf
      - .wsh
  filter_main_localassembly:
    TargetFilename|contains: \AppData\Local\assembly\tmp\
    TargetFilename|endswith: .dll
  filter_optional_webservicecache:
    TargetFilename|contains|all:
      - C:\Users\
      - \AppData\Local\Microsoft\Office\
      - \WebServiceCache\AllUsers
    TargetFilename|endswith: .com
  filter_optional_webex:
    Image|endswith: \winword.exe
    TargetFilename|contains: \AppData\Local\Temp\webexdelta\
    TargetFilename|endswith:
      - .dll
      - .exe
  filter_optional_backstageinappnavcache:
    TargetFilename|contains|all:
      - C:\Users\
      - \AppData\Local\Microsoft\Office\
      - \BackstageInAppNavCache\
    TargetFilename|endswith: .com
  condition: all of selection* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: c7a74c80-ba5a-486e-9974-ab9e682bc5e4
    type: derived

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