sigmamediumHunting

OneNote Attachment File Dropped In Suspicious Location

Detects creation of files with the ".one"/".onepkg" extension in suspicious or uncommon locations. This could be a sign of attackers abusing OneNote attachments

Detection Query

selection:
  TargetFilename|contains:
    - \AppData\Local\Temp\
    - \Users\Public\
    - \Windows\Temp\
    - :\Temp\
  TargetFilename|endswith:
    - .one
    - .onepkg
filter_main_onenote:
  Image|contains: :\Program Files\Microsoft Office\
  Image|endswith: \ONENOTE.EXE
condition: selection and not 1 of filter_main_*

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2023-01-22

Data Sources

windowsFile Events

Platforms

windows

References

Tags

attack.defense-evasion

Raw Content

title: OneNote Attachment File Dropped In Suspicious Location
id: 7fd164ba-126a-4d9c-9392-0d4f7c243df0
status: test
description: Detects creation of files with the ".one"/".onepkg" extension in suspicious or uncommon locations. This could be a sign of attackers abusing OneNote attachments
references:
    - https://www.bleepingcomputer.com/news/security/hackers-now-use-microsoft-onenote-attachments-to-spread-malware/
    - https://blog.osarmor.com/319/onenote-attachment-delivers-asyncrat-malware/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-01-22
modified: 2023-09-19
tags:
    - attack.defense-evasion
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|contains:
            # Note: add more common locations for drops such as download folders and the like. Or baseline legitimate locations and alert on everything else
            - '\AppData\Local\Temp\'
            - '\Users\Public\'
            - '\Windows\Temp\'
            - ':\Temp\'
        TargetFilename|endswith:
            - '.one'
            - '.onepkg'
    filter_main_onenote:
        Image|contains: ':\Program Files\Microsoft Office\'
        Image|endswith: '\ONENOTE.EXE'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Legitimate usage of ".one" or ".onepkg" files from those locations
level: medium