
title: Stealthy VSTO Persistence
author: Bhabesh Raj
date: 2021/01/10
description: Detects persistence via Visual Studio Tools for Office (VSTO) add-ins
  in Office applications.
detection:
  SELECTION_1:
    EventID: 12
  SELECTION_2:
    EventID: 13
  SELECTION_3:
    EventID: 14
  SELECTION_4:
    EventType: SetValue
  SELECTION_5:
    TargetObject:
    - '*\Software\Microsoft\Office\Outlook\Addins\\*'
    - '*\Software\Microsoft\Office\Word\Addins\\*'
    - '*\Software\Microsoft\Office\Excel\Addins\\*'
    - '*\Software\Microsoft\Office\Powerpoint\Addins\\*'
    - '*\Software\Microsoft\VSTO\Security\Inclusion\\*'
  SELECTION_6:
    Image: '*\msiexec.exe'
  condition: ((SELECTION_1 or SELECTION_2 or SELECTION_3) and (SELECTION_4 and SELECTION_5)
    and  not (SELECTION_6))
falsepositives:
- Unknown
id: 9d15044a-7cfe-4d23-8085-6ebc11df7685
level: high
logsource:
  category: registry_event
  product: windows
modified: 2021/07/27
references:
- https://twitter.com/_vivami/status/1347925307643355138
- https://vanmieghem.io/stealth-outlook-persistence/
status: experimental
tags:
- attack.t1137.006
- attack.persistence
ruletype: SIGMA
