Sigma rule: Office Macro File Download

Rule

Title

Office Macro File Download

Status

test

Level

low

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-01-23

Modified

2025-10-29

File

rules/windows/file/file_event/file_event_win_office_macro_files_downloaded.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of a new office macro files on the system via an application (browser, mail client).
This can help identify potential malicious activity, such as the download of macro-enabled documents that could be used for exploitation.

Log source

product

windows

category

file_event

Detection

selection_processes:
    Image|endswith:
        # Email clients
        - '\RuntimeBroker.exe' # Windows Email clients uses RuntimeBroker to create the files
        - '\outlook.exe'
        - '\thunderbird.exe'
        # Browsers
        - '\brave.exe'
        - '\chrome.exe'
        - '\firefox.exe'
        - '\iexplore.exe'
        - '\maxthon.exe'
        - '\MicrosoftEdge.exe'
        - '\msedge.exe'
        - '\msedgewebview2.exe'
        - '\opera.exe'
        - '\safari.exe'
        - '\seamonkey.exe'
        - '\vivaldi.exe'
        - '\whale.exe'
selection_ext:
    - TargetFilename|endswith:
          - '.docm'
          - '.dotm'
          - '.xlsm'
          - '.xltm'
          - '.potm'
          - '.pptm'
    - TargetFilename|contains:
          - '.docm:Zone'
          - '.dotm:Zone'
          - '.xlsm:Zone'
          - '.xltm:Zone'
          - '.potm:Zone'
          - '.pptm:Zone'
condition: all of selection_*

False positives (as the rule lists them)

• Legitimate macro files downloaded from the internet
• Legitimate macro files sent as attachments via emails

Tags

• attack.initial-access
• attack.t1566.001

MITRE ATT&CK ids this rule names

• T1566.001

Related rules

• 91174a41-dc8f-401b-be89-7bfc140612a0 (similar)

References

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1566.001/T1566.001.md
• https://learn.microsoft.com/en-us/deployoffice/compat/office-file-format-reference

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_office_macro_files_downloaded.yml