Suspicious Shim Database Patching Activity — Sigma Rule

Rule metadata and linked tags

Author: Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2023-08-01 / 2023-12-06.

{
  "category": "registry_set",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 919c5cce336da04f7b68c98b6a64a559722bb08ab3991c34ac896521e5d23107

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

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

Original YAML and metadata in JSON

False positives

• Unknown

Source 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