sigmalowHunting

Change Default File Association Via Assoc

Detects file association changes using the builtin "assoc" command. When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access or by administrators using the built-in assoc utility. Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened.

MITRE ATT&CK

T1546.001

privilege-escalationpersistence

Detection Query

selection_img:
  - Image|endswith: \cmd.exe
  - OriginalFileName: Cmd.Exe
selection_cli:
  CommandLine|contains: assoc
condition: all of selection_*

Author

Timur Zinniatullin, oscd.community

Created

2019-10-21

Data Sources

windowsProcess Creation Events

Platforms

windows

References

https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.001/T1546.001.md

Tags

attack.privilege-escalationattack.persistenceattack.t1546.001

Raw Content

title: Change Default File Association Via Assoc
id: 3d3aa6cd-6272-44d6-8afc-7e88dfef7061
related:
    - id: ae6f14e6-14de-45b0-9f44-c0986f50dc89
      type: similar
status: test
description: |
    Detects file association changes using the builtin "assoc" command.
    When a file is opened, the default program used to open the file (also called the file association or handler) is checked. File association selections are stored in the Windows Registry and can be edited by users, administrators, or programs that have Registry access or by administrators using the built-in assoc utility. Applications can modify the file association for a given file extension to call an arbitrary program when a file with the given extension is opened.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.001/T1546.001.md
author: Timur Zinniatullin, oscd.community
date: 2019-10-21
modified: 2023-03-06
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\cmd.exe'
        - OriginalFileName: 'Cmd.Exe'
    selection_cli:
        CommandLine|contains: 'assoc'
    condition: all of selection_*
falsepositives:
    - Admin activity
level: low
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_cmd_assoc_execution/info.yml