Shell32 DLL Execution in Suspicious Directory — Sigma Rule

Rule metadata and linked tags

Author: Christian Burkard (Nextron Systems). Source status: test; severity: high. Source dates: 2021-11-24 / 2023-02-09.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 93e5a1c863ce51e31f010d12794cc387ccad996357dd48b82effab2210c47797

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: Shell32 DLL Execution in Suspicious Directory
id: 32b96012-7892-429e-b26c-ac2bf46066ff
status: test
description: Detects shell32.dll executing a DLL in a suspicious directory
references:
    - https://www.group-ib.com/resources/threat-research/red-curl-2.html
author: Christian Burkard (Nextron Systems)
date: 2021-11-24
modified: 2023-02-09
tags:
    - attack.execution
    - attack.stealth
    - attack.t1218.011
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|contains|all:
            - 'shell32.dll'
            - 'Control_RunDLL'
        CommandLine|contains:
            - '%AppData%'
            - '%LocalAppData%'
            - '%Temp%'
            - '%tmp%'
            - '\AppData\'
            - '\Temp\'
            - '\Users\Public\'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.group-ib.com/resources/threat-research/red-curl-2.html