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Detection rules › Sigma

New Custom Shim Database Created

Status
test
Severity
medium
Log source
product windows, category file_event
Author
frack113, Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by application shims. The Microsoft Windows Application Compatibility Infrastructure/Framework (Application Shim) was created to allow for backward compatibility of software as the operating system codebase changes over time.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1547.009 Boot or Logon Autostart Execution: Shortcut Modification
Privilege EscalationT1547.009 Boot or Logon Autostart Execution: Shortcut Modification

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: New Custom Shim Database Created
id: ee63c85c-6d51-4d12-ad09-04e25877a947
status: test
description: |
    Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by application shims.
    The Microsoft Windows Application Compatibility Infrastructure/Framework (Application Shim) was created to allow for backward compatibility of software as the operating system codebase changes over time.
references:
    - 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: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2021-12-29
modified: 2023-12-06
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:
    - Legitimate custom SHIM installations will also trigger this rule
level: medium
regression_tests_path: regression_data/rules/windows/file/file_event/file_event_win_creation_new_shim_database/info.yml

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|contains:
        - ':\Windows\apppatch\Custom\'
        - ':\Windows\apppatch\CustomSDB\'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
TargetFilenamematch
  • :\Windows\apppatch\CustomSDB\
  • :\Windows\apppatch\Custom\