Suspicious Creation of New Custom Shim Database (via file_event)

title: Suspicious Creation of New Custom Shim Database (via file_event)
id: 49a8119b-7282-550d-b22b-784093e25cfa
status: stable
description: This rule detects threat actors may establish persistence and/or elevate privileges by running hostile content triggered by application shims. The Microsoft Windows Application Compatibility Infrastructure/Framework (Application Shim) was created to enable for backward compatibility of software as the operating system codebase changes over time.
references:
    - https://attack.mitre.org/techniques/T1547/009/
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.011/T1546.011.md#atomic-test-2---new-shim-database-files-created-in-the-default-shim-database-directory
    - https://www.mandiant.com/resources/blog/fin7-shim-databases-persistence
    - https://liberty-shell.com/sec/2020/02/25/shim-persistence/
    - https://andreafortuna.org/2018/11/12/process-injection-and-persistence-using-application-shimming/
author: Huntrule Team
date: 2026-06-14
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547.009
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|contains:
            - ':\Windows\apppatch\Custom\'
            - ':\Windows\apppatch\CustomSDB\'
    condition: selection
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/file/file_event/file_event_win_creation_new_shim_database/info.yml