Suspicious Shim Database Patching Activity

SIGMA detection rule by Nasreddine Bencherchali (Nextron Systems) · NOASSERTION

Detects installation of new shim databases that try to patch sections of known processes for potential process injection or persistence.

title: Suspicious Shim Database Patching Activity
id: bf344fea-d947-4ef4-9192-34d008315d3a
status: test
description: Detects installation of new shim databases that try to patch sections of known processes for potential process injection or persistence.
references:
    - https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/pillowmint-fin7s-monkey-thief/
    - https://www.fireeye.com/blog/threat-research/2017/05/fin7-shim-databases-persistence.html
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-01
modified: 2023-12-06
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.011
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: '\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Custom\'
        TargetObject|endswith:
            # Note: add other application to increase coverage
            - '\csrss.exe'
            - '\dllhost.exe'
            - '\explorer.exe'
            - '\RuntimeBroker.exe'
            - '\services.exe'
            - '\sihost.exe'
            - '\svchost.exe'
            - '\taskhostw.exe'
            - '\winlogon.exe'
            - '\WmiPrvSe.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

0d4109c6-90f8-4645-a50c-9bca6f679101

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

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