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Uncommon Microsoft Office Trusted Location Added

Detects changes to registry keys related to "Trusted Location" of Microsoft Office where the path is set to something uncommon. Attackers might add additional trusted locations to avoid macro security restrictions.

MITRE ATT&CK

T1112

persistencedefense-evasion

Detection Query

selection:
  TargetObject|contains: Security\Trusted Locations\Location
  TargetObject|endswith: \Path
filter_exclude_known_paths:
  Details|contains:
    - "%APPDATA%\\Microsoft\\Templates"
    - "%%APPDATA%%\\Microsoft\\Templates"
    - "%APPDATA%\\Microsoft\\Word\\Startup"
    - "%%APPDATA%%\\Microsoft\\Word\\Startup"
    - :\Program Files (x86)\Microsoft Office\root\Templates\
    - :\Program Files\Microsoft Office (x86)\Templates
    - :\Program Files\Microsoft Office\root\Templates\
    - :\Program Files\Microsoft Office\Templates\
filter_main_office_click_to_run:
  Image|contains: :\Program Files\Common Files\Microsoft Shared\ClickToRun\
  Image|endswith: \OfficeClickToRun.exe
filter_main_office_apps:
  Image|contains:
    - :\Program Files\Microsoft Office\
    - :\Program Files (x86)\Microsoft Office\
condition: selection and not 1 of filter_main_* and not 1 of filter_exclude_*

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2023-06-21

Data Sources

windowsRegistry Set Events

Platforms

windows

References

Tags

attack.persistenceattack.defense-evasionattack.t1112

Raw Content

title: Uncommon Microsoft Office Trusted Location Added
id: f742bde7-9528-42e5-bd82-84f51a8387d2
related:
    - id: a0bed973-45fa-4625-adb5-6ecdf9be70ac
      type: derived
status: test
description: Detects changes to registry keys related to "Trusted Location" of Microsoft Office where the path is set to something uncommon. Attackers might add additional trusted locations to avoid macro security restrictions.
references:
    - Internal Research
    - https://admx.help/?Category=Office2016&Policy=excel16.Office.Microsoft.Policies.Windows::L_TrustedLoc01
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-06-21
modified: 2023-09-29
tags:
    - attack.persistence
    - attack.defense-evasion
    - attack.t1112
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: 'Security\Trusted Locations\Location'
        TargetObject|endswith: '\Path'
    filter_exclude_known_paths:
        Details|contains:
            - '%APPDATA%\Microsoft\Templates'
            - '%%APPDATA%%\Microsoft\Templates'
            - '%APPDATA%\Microsoft\Word\Startup'
            - '%%APPDATA%%\Microsoft\Word\Startup'
            - ':\Program Files (x86)\Microsoft Office\root\Templates\'
            - ':\Program Files\Microsoft Office (x86)\Templates'
            - ':\Program Files\Microsoft Office\root\Templates\'
            - ':\Program Files\Microsoft Office\Templates\'
    filter_main_office_click_to_run:
        Image|contains: ':\Program Files\Common Files\Microsoft Shared\ClickToRun\'
        Image|endswith: '\OfficeClickToRun.exe'
    filter_main_office_apps:
        Image|contains:
            - ':\Program Files\Microsoft Office\'
            - ':\Program Files (x86)\Microsoft Office\'
    condition: selection and not 1 of filter_main_* and not 1 of filter_exclude_*
falsepositives:
    - Other unknown legitimate or custom paths need to be filtered to avoid false positives
level: high