Potential Persistence Via Outlook Form


Description

Detects the creation of a new Outlook form which can contain malicious code

Query · sigma

selection:
  Image|endswith: \outlook.exe
  TargetFilename|contains:
  - \AppData\Local\Microsoft\FORMS\IPM
  - \Local Settings\Application Data\Microsoft\Forms
condition: selection

Known false positives

  • Legitimate use of outlook forms
Raw source Potential Persistence Via Outlook Form · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified.
title: Potential Persistence Via Outlook Form
id: c3edc6a5-d9d4-48d8-930e-aab518390917
status: test
description: Detects the creation of a new Outlook form which can contain malicious code
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=76
    - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=79
    - https://learn.microsoft.com/en-us/office/vba/outlook/concepts/outlook-forms/create-an-outlook-form
    - https://www.slipstick.com/developer/custom-form/clean-outlooks-forms-cache/
author: Tobias Michalski (Nextron Systems)
date: 2021-06-10
modified: 2023-02-22
tags:
    - attack.persistence
    - attack.t1137.003
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith: '\outlook.exe'
        TargetFilename|contains:
            - '\AppData\Local\Microsoft\FORMS\IPM'
            - '\Local Settings\Application Data\Microsoft\Forms' # Windows XP
    condition: selection
falsepositives:
    - Legitimate use of outlook forms
level: high

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